Kai

Kai is the current Elemental Master and Ninja of Fire, and Nya's older brother. He and his younger sister worked as blacksmiths in their father's blacksmith shop. With the help of Master Wu, Kai learned Spinjitzu and discovered his other teammates, with whom he embarked on many adventures as they battled the Serpentine and the Stone Army. After Zane's sacrifice to destroy the Golden Master, the Ninja parted ways before reuniting to rescue Zane on Chen's Island. There, Kai grew closer to Skylor as they competed in the Tournament of Elements. Ultimately, he allied with the other Elemental Masters to defeat Chen's army. After the war ended, Lloyd was possessed by Morro, who escaped the Cursed Realm and released a legion of ghosts. Kai and the Ninja battled Morro and his forces before the Cursed Realm was destroyed.

The Ninja found fame after saving Stiix, but when Nadakhan returned with the Sky Pirates, he trapped Kai and the other Ninja in the Sword of Souls. Jay freed him and reversed recent events with his final wish. On the Day of the Departed, Kai and Nya fought a revived Chen, who they defeated once more. When the Time Twins returned to Ninjago, Kai and Nya reunited with their parents and stopped Krux and Acronix from changing the future. They managed to follow them through time and stopped them before Wu sent Kai and Nya back to the present, while Wu ended up lost in time.

Kai and the Ninja later watch over Harumi, after she lost her adopted parents, until the discovery that she secretly is the leader of the Sons of Garmadon and wants to resurrect Lord Garmadon. Despite the Ninjas' efforts, Harumi successfully resurrects Garmadon, and shortly after, Kai ends up in the Realm of Oni and Dragons with Cole, Jay, Zane, and the rapidly aging Wu. They are also forced to deal with the threat of the Dragon Hunters and dragons as they pursue the Dragon Armor to return to Ninjago.

Early life
Kai was born in Ignacia, the first child of a blacksmith who owned the Four Weapons shop. He and his younger sister, Nya, were raised in their father's craft. Unknown to either of them, their parents were the Elemental Masters of Fire and Water. Kai inherited his father's element of Fire while Nya inherited their mother's ability of Water though they were unaware of this fact.

When his parents disappeared, Kai took it upon himself to keep the family business going, vowing to surpass his father's black smith skills. Kai also took care of his sister while wondering what became of their parents.

Way of the Ninja
One day while working, Kai explained to Nya how to make a sword, but became too impatient and thus produced a disfigured weapon. He was quickly reminded to be patient by his sister, only to be interrupted as an old man arrived. Yet the potential customer began voicing complaints concerning the lack of tools for Ninja, and Kai quickly shooed him away.

Shortly thereafter, Ignacia fell under attack by Samukai and his Skeleton army. Kai attempted to defend it with the samurai armor he made, though it proved to be slow and clunky. While he managed to defeat several skeleton foot soldiers, he was quickly subdued by Samukai. Pinned down by his armor, Kai would have fallen victim to the Skulkin General had the old man—Master Wu—not returned and saved him. However, while they were preoccupied, the skeletons kidnapped Nya and escaped to the Underworld. The young blacksmith intended to go after them, but was told by Wu of the First Spinjitzu Master and his two sons who fought over the four Golden Weapons, explaining that an honest man—Kai's father—had been entrusted with the map to their resting places. He was advised by Wu to become a Ninja and Kai reluctantly agreed in the hopes of saving his sister.

Kai was taken to the Monastery of Spinjitzu in order to be trained as a Spinjitzu master so he could save his sister, and all of Ninjago. During his training, Kai had to learn patience and how to harness the "fire" inside of him. This training consisted of running a course before Master Wu finished his tea. Kai accomplished this after several days and attempts by knocking the teacup out of Master's hands when he was about halfway through the course with his wooden training sword. However, he was then told by Wu that he had one final test the next day and was advised to get some sleep.

The Golden Weapon
Later that night, while Kai was pondering Master Wu's training and brushing his teeth, he was set upon by three black-suited Ninja. Their fight took them out to the courtyard where the blacksmith activated the training course to even the odds. They were quickly stopped however by Wu, who revealed that the three Ninja were his students as well. Wu then used Creation to give each of the Ninja a suit that matched their elemental properties, and pronounced Kai as the red Master of Fire. After Wu explained their purpose, he announced that they would now leave to claim the first Golden Weapon.

Once arriving at the Caves of Despair, Kai ran ahead of the other Ninja while Cole was still formulating a plan, intending to find the weapon himself. The others caught up to him at Samukai's watch tower, and after Zane stole the map, Kai raced ahead again. The other Ninja followed him and caught up to the Red Ninja once more as he was attempting to remove the boulder blocking the entrance. Cole reminded him that they were a team as they moved it together. Jay then accidentally revealed their position to the skeleton army digging for the weapon, and they were soon in a battle. After Jay discovered the key to unlocking his Spinjitzu, Kai and the others were quick to follow. They used it to drive off the skeleton army, after which they discovered that they had a bigger problem in the form of the weapon's guardian, the Earth Dragon. Kai happened to be holding the Scythe at the time, and decided that the only way out was to use it, contrary to Master Wu's instructions. After escaping, Kai was strictly reprimanded by Master Wu, and they went onward toward the next weapon, the Shurikens of Ice.

King of Shadows
While on their way to the Frozen Wasteland, the location of the Shurikens, Wu told the Ninja about the most powerful technique in Spinjitzu, the Tornado of Creation. Kai began to attempt it, but was stopped by Master Wu, who explained that it could have disastrous consequences if done incorrectly.

After they succeeded in finding the Shurikens, the Ninja ascended to the Floating Ruins for the Nunchucks of Lightning. After retrieving it, they used Jay's gliders to descend into the Forest of Tranquility, where they made camp. Kai was suddenly awoken in the middle of the night and lured to the Fire Temple by Garmadon who was holding Nya there. Kai was forced to remove the Sword of Fire from its pedestal to cut the chain and save his sister. He was then attacked and defeated by his own shadow under Garmadon's manipulation, but Master Wu arrived before the dark lord could claim the sword. Realizing it had just been a trap to lure them away from the other Ninja, the three attempted to escape but were stopped by the Fire Dragon. As a last resort, Wu sacrificed himself and ventured into the Underworld with the Sword of Fire. While his act kept the four Golden Weapons apart, Kai and Nya were still left in the hands of the Fire Dragon.

Weapons of Destiny
Luckily the Fire Dragon soon realized that they were simply trying to protect the weapons and by the time Cole, Jay, and Zane arrived, Kai and Nya had befriended the Dragon. As the dragons were able to cross over into the Underworld, Kai urged the other Ninja to hop on though Cole, who feared dragons, pointed out that there wasn't enough room. This inspired Kai to have the Ninja befriend the other dragons and together they successfully crossed into the Underworld.

The Ninja attempted to use the stalactites to sneak past the guards of the Skulkin fortress but accidentally grabbed onto the legs of a Spykor. Out of fear Kai and the others fell to the ground outside the fortress where they were quickly surrounded by Skulkin and spykors alike. With their options limited Jay suggested they perform the Tornado of Creation and the Ninja successfully performed the technique, turning the fortress into a ferris wheel prison. The Ninja descended into the throne room where Master Wu was dueling Samukai for the Golden Weapons, though Kai forbade the other Ninja to interfere as it was their master's fight. Wu was quickly defeated, though when Samukai took the Sword of Fire, a portal between dimensions was formed, allowing Garmadon to escape from the Underworld. Knowing that he would one day return, Kai took the Sword of Fire and vowed to protect the weapon.

Kai and the other Ninja returned to Four Weapons where they were reunited with Nya and assured the villagers they would be ready when Garmadon returned.

Flight of the Dragon Ninja
Cole, Zane, Jay, and Kai were told to train by Master Wu, but instead opted to spend their time racing their dragons. After Jay won a race and began bragging about his skills, Kai and the others challenged him to another race over the forest and back, with the winner becoming "Dragon Master" for a month. Zane objected, feeling that the Ninja should be training, to which Kai replied that riding their dragons was a form of training.

As the race began, Kai and Zane flew their dragons over the clouds, where they briefly dueled each other with their dragons' elemental breath attacks. On the home stretch, they were all neck-and-neck, but Cole won when he "activated the turbo"—a roasted chicken dangled in front of his dragon's nose. Once the others landed, Kai congratulated Cole on the win, but said that they would get him the next day. When Cole reminded him that the winner was supposed to be "Dragon Master" for a month, Kai and the others denied ever agreeing to the bet.

The New Masters of Spinjitzu
After retrieving the Sword of Fire, Kai placed it on a stand above his bed. One night, Nuckal and Kruncha infiltrated the Monastery of Spinjitzu to steal the Golden Weapons from the sleeping Ninja. Although the theft went off without a hitch, Kai was awoken when the Skulkin Generals lost control of the weapons and accidentally activated the training course. Half-asleep, Kai went outside to shut the course off, irritably reminding Jay that he had to repair whatever flaw was causing it to turn itself on. With that, Kai went back to sleep, completely unaware of Kruncha and Nuckal's presence in the Monastery even as they returned the Golden Weapons and fled to blame each other for coming up with the plan.

Return to the Fire Temple
The Fire Dragon, Flame, flew Kai and Nya to the Fire Temple, wanting to show them something. After dismounting the Dragon, Flame led Kai to a passage connecting Ninjago to the Underworld. Kai started planning what to do when the ground fell out from beneath him. Krazi alerted Wyplash, who sent several Skulkin after him. He disarmed his enemies, but they picked him up. Nya and Flame then shot a blast of heat scaring the Skulkin and sealing the passage.

Darkness Shall Rise
In the aftermath of the Great Devourer's defeat, Kai and his friends spent much time cleaning up the great serpent's venom from around the city.

Meanwhile, Garmadon appeared to have survived his fight with the Great Devourer, and showed up where the serpentine were gathering. He used the Golden Weapons to recreate the Destiny's Bounty in a dark image. This convinces them to join him except for Skales, Fangtom, Acidicus, and Skalidor who were angry that there Serpentine brothers would leave them for a non-Serpentine. As The Ninja adjusted to their reduced powers (thanks to the loss of their Golden Weapons), their thoughts turned to finding a new home and training Lloyd for the inevitable battle with Lord Garmadon. A local woman offered boarding in her hotel, but Kai balked at the state of the suite they could afford.

Deciding that they needed to live in comfort before they could properly train Lloyd, the Ninja opted for a lavish suite and took up jobs around the city to pay for the rent, with Kai taking up a job as an entertainer at children's parties. Jay became a pizza delivery man, and Cole got a job as a guard of a bank. Zane began his culinary career when he became a chef at a restaurant. Being occupied by their new jobs, the Ninja had limited time to train Lloyd, but were too tired to train him. When Jay had to deliver a pizza to the middle of nowhere, he looks down into the sewer because it was the only thing around. He witnesses Fangtom, Acidicus, and Skalidor plotting to rob a bank. Skalidor complains about being hungry, and asks when the pizza will arrive. At that moment, Skales appears behind Jay and abducts him.

When the other Serpentine leaders rob the bank, Kai, who was entertaining nearby, ran off the job to get there, resulting him getting fired.

Pirates Vs. Ninja
Kai and the other Ninja began to properly train Lloyd, though soon realized their apartment wasn't the most suitable place. Wu sent them out into the city to look for a better training ground and they soon found Grand Sensei Dareth's Mojo Dojo. There they asked the owner Dareth if they could share the space to which he agreed if one of them could best him in a fight. While Dareth was showing off all his animal styles, Kai used Spinjitzu to send him to the ground, thus winning the fight.

Following their first session training Lloyd in the dojo, the Ninja exited to find the city under attack by Captain Soto's pirates. The Ninja quickly boarded a bus and raced towards the boat. After stopping by Wong's Costume to disguise themselves as pirates, Kai and the others boarded the ship and confronted Soto's crew. After a brief fight and with the help of the Ninja, the pirates were eventually subdued.

Double Trouble
Jay assisted in helping Lloyd use his Green Ninja power to light a light bulb at Dareth's Mojo Dojo. Despite the Ninjas' encouragement, Lloyd fails to light a light bulb and became mad. Just then, Nya rushed into the room carrying a letter stating that Lloyd's old school, Darkley's School for Bad Boys, has changed to Darkley's School for Great Children, and that they wanted to Lloyd to receive an honorary award of excellence.

Kai and the others flew on the Ultra Dragon to the school where they are locked inside a room and discover that the students there had set it all up to get revenge on Lloyd. After very careful thinking, Kai and the Ninja escaped the 'prison' only to find that Garmadon had create evil duplicates of the Ninja, who had infiltrated the school and were attacking the students. The Ninja could not let the evil Ninja hurt anyone, so they attacked their evil counterparts. They would have been defeated if it weren't for the students coming to the rescue and confusing the evil Ninja, who let their guard down and were defeated.

Ninjaball Run
Kai, along with the other Ninja, compete in the Ninjaball Run to win the prize of $500 in order to save Dareth's Mojo Dojo. The Ninja race in the Ultra Sonic Raider. Lloyd flies on the Ultra Dragon so that they have a better chance of winning the race. They race through dangerous terrain, and eventually Lloyd and his dragon crash putting him out of the race.

Child's Play
As the Ninja are trying to train Lloyd, they find out that he was anticipating to get the new issue of the "Starfarer" comic. Nya then came in to tell them to stop Garmadon, who broke into the Museum. After stopping them from reviving the Grundle, they realized they were turned into kids. When noting the Serpentine is stealing a sarcophagus, they chased them, but noticed they're kids and that Garmadon's Mega Weapon did work. Eventually, the police came and accused them for stealing.

The Curator forgave them, asked what happened to the Grundle bones, which was missing. They explained it's been revived, but they didn't believe them, prompting them to escape by disguising themselves. They called Lloyd to meet them at Buddy's Pizza with their weapons. Lloyd then tells them he knows who can help them.

They went into a comic book store, where Lloyd introduces them to Rufus MacAllister. Rusus explained weapons are no use against the Grundle and that light, such as from an illumisword, can defeat it. After hearing they must be won, the Ninja motivated Lloyd to enter.

Lloyd, however, lost just before the Grundle came. They tried to get the door opened, but it's jammed. They grabbed the illumiswords, but they easily broke. Wu gave them the Tomorrow's tea, but hesitated to turn Lloyd into a teen. Lloyd threw the tea for them, ultimately defeating the Grundle.

Wrong Place, Wrong Time
Lord Garmadon uses the Mega Weapon to go back in time and make it so that Lloyd would never become the green Ninja. The Ninja later find out about his plan and jump into the portal Garmadon created with his Mega Weapon to stop him. The Ninja get back in time and fall through a portal. They find themselves in Ignacia, at the time Wu came to Kai's shop and even before Skulkins attacked the land. They catch old Wu and explained him about the situation. This time, skeletons didn't kidnap Nya and Kai from the past had no will to become a Ninja. Wu then leads him and Nya to the monastery. The Ninja decided to dress like skeletons and kidnap Nya so past Kai can get a reason to become the Ninja. They did that, and Garmadon took Nya to the Fire Temple. Present Kai reveals himself to his past self, and they work together to defeat Garmadon. They succeed by destroying the Mega Weapon and Kai, along with other Ninja, comes back safely.

The Stone Army
After the Ninja reluctantly woke up for sunrise exercises, Wu told them they have to clean up the Ultra Dragon. They left Lloyd to do the job alone, but after he said it's not fair, they played a round of Rock, Paper, Clamp, with Lloyd losing. Before he started cleaning, he informed them that he lived at Darkley's School most of his life and that he doesn't remember his mother. Nya came along and told them the Museum needs their assistance.

The museum's curator showed them to the gift shop and said the Great Devourer's venom bought the Stone Warrior merchandise to life. The Ninja tried to keep it under control, but wrecked the place in the process. When the Ninja met up with Wu, he introduced them to Misako, Lloyd's mother. When Misako tries to explain to Lloyd why she abandoned him, the Ninja watched him as he walked away.

After finding Misako and Lloyd at the Bottomless Pit exhibit, Misako explained to them about the Overlord. When the Giant Stone Warrior bursted in, Kai was told to defeat it, but his katana broke and was thrown into a large vase. They eventually ran from the Warrior. Lloyd told them to distract him, to which Kai and the others agreed. They did just that, but have to run away after it broke free.

The Day Ninjago Stood Still
Kai helped train Lloyd to fight without using his eyes in Dareth's dojo, but they were soon interrupted by a series of earthquakes. They halted their training to tune into the news and learned that the aftershocks were getting worse. Kai immediately blamed Garmadon, though Misako pointed out that the Dark Lord would never do anything to harm his son.

The Ninja began to patrol the city for danger and even save a woman who was trapped by the collapsing street. The city soon falls under attack by the Stone Army and Master Wu orders the Ninja to send everyone to the NGTV office tower where they can be evacuated by the Destiny's Bounty. The citizens all climb to the roof while the Ninja hold off the Stone Warriors using the Ultra Sonic Raider and the Ultra Dragon. Kai continues to help hold off the Stone Army.

The Last Voyage
The Ninja sail to the Dark Island on the flightless Destiny's Bounty. Along the way they run into a storm and the ship-eating Starteeth. When the storm passes the ship, which now is missing a rudder and has a hole in the side, the ship runs ashore on an island with a prison tower. After Dr. Julien told him the Skulklin trapped him there, he agreed to help fix the Bounty. The Ninja and Dr. Julien left the prison and continued their journey to the Dark Island.

Island of Darkness
The Ninja finally arrive on the Island of Darkness, where the Stone Army is preparing for the final battle. The Ninja learn that the Temple of Light is where they can receive their elemental powers. In order to do this, the Ninja must use a medallion to find the temple. Later Jay was able to find the Temple of Light by aligning three lights with the holes in the medallion—the temple is at the top of the island's highest mountain.

With their new vehicles, the Ninja head for the Temple of Light, barely keeping ahead of the Stone Army. Inside the Temple, they find pictures on the walls depicting their journey from the past until the present. Further in is a great bell, hanging above a strange design on the floor bearing the Ninja's symbols. Realizing that it's the Instrument of Peace, Lloyd strikes it, causing a light to shine on him and beams of energy to reflect off crystals in the walls. Soon, the entire room is crisscrossed with beams, and one hits a pillar, making it glow brightly. At the foot of the pillar, Kai's armor transforms, and an Elemental Blade with the power of Fire appears in his hand as well as the other Ninja. As their swords manifest blades representing their respective elements, Lloyd rises into the air. The Ninja use their swords to send their elemental powers to Lloyd.

The Stone Army finally marches into the Temple, but the Ninja are more than ready for them—using their new elemental powers, they easily trounce the warriors. Kai beats up some soldiers within a ring of fire. Finally, Lloyd summons the power of the Golden Dragon, creating a brilliant light that frightens the remaining stone soldiers into retreat.

The Last Hope
At the beach, Dr. Julien repairs the Falcon, while the Ninja celebrate their restored powers by shooting down coconuts. The party is interrupted by Master Wu, who chastises the Ninja for their unseemly mirth; they may have the power to defeat the Stone Army, but the Celestial Clock is still counting down to the final battle between light and darkness. At that, Misako reveals a way to at least delay the battle: if the Helmet of Shadows is returned to its pedestal, the countdown might stop long enough for them to gain an advantage. Risking everything, the Ninja disguise themselves as Stone Warriors and escort Misako to Lord Garmadon's camp. As General Kozu takes Misako to his master's tent, the disguised Ninja are put to work carrying Dark Matter to the super-weapon. The weapon is surrounded by a wooden wall, but the Ninja notice one protruding detail—a very large cannon—and ponder what Garmadon plans to attack with it. Later the Ninja are, forcing them to fight their way back down to the entrance as Misako rejoins them.

The Ninja make their escape with Misako and Nya in the power drill, but the Stone Army pursues them until the Overlord reminds Lord Garmadon that the Ninja could turn the army against him if they don the Helmet. After a frantic chase that ends in the Power Drill being disabled momentarily, Garmadon goes for the kill, only for Lloyd to blast it with his powers. Lord Garmadon emerges from the wreckage, weakened and vulnerable; from the Power Drill, the Ninja encourage Lloyd to finish him off. Despite everything at stake, the Green Ninja is unable to strike the fatal blow, forcing him to jump aboard the Power Drill as the Ninja make their escape from the advancing Stone Army.

At the Celestial Clock, the Ninja meet with Master Wu and desperately look for the Helmet's pedestal with minutes to spare. As the Stone Army arrives, the Ninja find the pedestal and replace the Helmet, but it's one second too late; the countdown has ended and the final battle is upon them. As the clock fires a mighty energy flare inland, the Stone Army captures Nya and the Ninja are sent down into a crevasse. Surviving the fall, the Ninja head off to prepare for the final battle.

Return of the Overlord
Kai returned with the other Ninja to the beach where the Bounty was hidden and met up with Dr. Julien. As Wu and Misako attempted to raise Lloyd's spirits to face his father in the final battle, Kai pledged his fire to the Green Ninja and prepared for battle.

The heroes set off to Garmadon's camp, intending to begin the final battle, but were surprised to find it deserted upon arrival. Misako quickly realized that the Stone Army intended to use the ultimate weapon on Ninjago to shift the balance and allow the Overlord to cross over, thus the Ninja followed the machine's tracks in the hopes of stopping it before it was fired.

As the Ninja ran, they recalled memories of their past adventures until they were ambushed by Nya, whom had been turned evil by Garmadon's Dark Matter. Kai urged Wu, Misako, and Lloyd to continue on ahead while he and the other Ninja fended Nya off.

While at first having a hard time stopping for fear of injuring his sister, Kai quickly realized a way to trap Nya using their Elemental Powers, and before long they were on their way again.

The Ninja arrived at the beach in time to witness the Overlord take control of Garmadon's body, having fired enough Dark Matter into Ninjago to allow him to cross over. Reassuring Lloyd that they stood behind him, Kai and the other Ninja raced into battle to defeat the Stone Army. Kai used his Elemental Blade to cut one of the Stone Army's machines in half before commandeering one of Garmatron's cannons. As Lloyd faced the Overlord, Kai watched with the other Ninja as their comrade was defeated. The Overlord proceeded to open a portal to Ninjago, though it closed just as the Red Ninja attempted to pass through it.

Rise of the Spinjitzu Master
Hitching a ride on Kai's Fire Robot, the Ninja returned to the Temple of Light, where they activated a hidden mechanism that revealed the Golden Mech. When Lloyd sat in the cockpit, his powers as the Chosen One restored the ancient machine to fighting form. With the Ultra Dragon's arrival to the Island of Darkness, the group was able to return to Ninjago City, only to find it infected with Dark Matter and ruled by the Overlord, now restored to his monstrous true form. Despite their fighting prowess, the heroes were almost overwhelmed by the Stone Army, only to be saved when Dareth donned the Helmet of Shadows and took command of the ancient soldiers.

Kai and the other Ninja proceeded to ascend the tower but only to watch them fall victim to the Overlord's corruption. Later he distracts Nya and Lloyd was forced to limp up to the top of the tower alone, where the Overlord was waiting. In the aftermath of the Overlord's defeat, all of his creations and corruption vanished. Kai reunited with his allies in the crater left by the Garmatron's disappearance.

The Surge
Following the defeat of the Overlord, Ninjago entered an era of peace. Without an enemy to fight, the Ninja were no longer needed and thus began teaching at Master Wu's Academy. At one point, Kai was caught on video by Jay singing in the shower.

During break on a rather stressful day, Nya approached Kai and the other Ninja and informed them they had received clearance for a field trip to Borg Industries. This didn't interest the Red Ninja who believed people should be learning from the past instead of wasting time on new technology, though he boarded the bus anyway.

Upon arriving at Borg Tower, Kai became stuck between the automatic doors, freeing himself just in time to board the elevator with the other Ninja as Cyrus Borg had requested to see them personally. After being introduced to the inventor, Kai questioned why the tower had been built atop where the Overlord had been defeated. Borg then presented them with a statue of himself as a gift for the Ninja, but promptly pulled Kai aside and ordered the Red Ninja to protect "them" with his life.

As the Ninja left with the statue, they accidentally dropped it and discovered new gis and the Techno Blades inside. Suddenly a robotic security voice in the elevator says that they should drop the blades. The Ninja refuse, and the elevator drops toward the ground at high speed. The Ninja luckily escape into an elevator going up right next to it, and manage to get their new outfits on for battle in their escape from Borg Tower.

When they get down of the tower, Master Wu takes the Techno Blades and says that he wants Kai and Zane in the air. Kai jumps on Zane's copter and hacks an enemy airplane, making it the Kai Fighter and reaching the outer space. While he was flying, Cyrus Borg gives him a visual message saying that few weeks ago they discovered that new virus, Digital Overlord, in the industries' system. He also says that they have to bring the Techno Blades out of the city, because if he finds out that they have them, he will never let them leave. After that, Kai gets into the sky fight with virus controlled planes. In the moment they almost get destructed, Lloyd comes on the Golden Dragon, defeating the robots. As the Ninja get back into the vehicles and get on the road outside of the city, Overlord spots that Wu is getting away with the Techno Blades so he sends two copters which capture him on the building roof. However before that happened, Wu quickly dropped Techno Blades into Kai's Fighter so the Ninjas could safely get them out of the city, while Wu gets captured by Overlord's forces.

The Art of the Silent Fist
After escaping from New Ninjago City, the Ninja are hides their vehicles. Misako then greets them and shows them to the Monastery, but Zane offers stay behind with the Techno Blades, as Garmadon (whom is now "Master Garmadon,") forbids any weapons in his monastery. As night falls, Garmadon arrives and teaches the Ninja and his students about "the art of the silent fist." While everyone inside is practicing the technique, Zane catches P.I.X.A.L. and tie her up, then returns to the Monastery as the Ninja come out to see what is going on. Zane then uses his Techno Blade to hack P.I.X.A.L.'s systems, freeing her from the Overlord's control. Grateful to Zane for saving her, P.I.X.A.L. tells the Ninja of Master Wu.

Suddenly, P.I.X.A.L. realizes she did not come alone and Nindroids surround the place. The Ninja successfully defeat the Nindroids by trapping them into mill wheel which then roll out. However, General Cryptor destroys the Ninja's vehicles. After that, the Ninja decides to split. Jay, Zane, Cole, Kai, and Nya gets an idea to shut down the power in the city to stop virus controlling machines in the land. As night falls, they arrive to the station, but with high guard of Nindroids. They manage to get inside but can't find the way to break the power charge. When Cryptor sends Nindroids inside, Kai remembers Garmadon's lesson of fighting without fighting so they decide to lure Nindroids to destroy the charge which then explodes and all the power disappears, including P.I.X.A.L. who gets shut down.

Blackout
The Ninja have gone to Ed & Edna's Scrap N Junk to look for parts that would enable Zane's hover-copter to run on solar power. While Ed, Jay, Cole, and Kai search through the junk piles, Nya transfers half of Zane's power source to P.I.X.A.L.. Unbeknownst to the Ninja, Techno Wu arrives via hover-copter and powers General Cryptor, along with a few Nindroid Warriors, using electrocobrai. After activating a few Nindroids, Min-Droid sneaks and gets access to Ed & Edna's crane. The tiny droid uses the crane and launches the truck at a garbage pile.

Kai realizes and quickly informs his friends; the Ninja perform Spinjitzu and get out of the fallen vehicle, while Ed and Edna escape using bubble jet-packs. Meanwhile Jay and Cole are captured, Kai battles Wu clanging their weapons against one another. Eventually Wu manages to fling Kai away. Nya frees Jay and Cole and they assists Kai. However, Wu traps the Ninja in a corner, but Zane and P.I.X.A.L. come with a magnified vehicle and pick up Wu since he is now part metal. The Ninja are excited, but quickly ends when the Stranger frees Wu and flies away with their via hover-copter. However, the Stranger leaves a scale behind. Nya decides to give Lloyd and Garmadon a message.

The Curse of the Golden Master
The Hover-copter was eventually converted to solar power, the Ninja returned to New Ninjago City with Nya and P.I.X.A.L. There, they reunited with Borg and explained their suspicions as to who stole the hard-drive containing the Overlord.

They eventually came across the Stone Army Tomb, only to find the seal had been opened. Upon confronting Skales, they learned that the Serpentine had reformed and the Snake King even had a son. The Ninja and Nya were lead to a campfire where Acidicus told them of the Curse of the Golden Master, and how they believed it was referring to Lloyd. While the Ninja discussed the curse, Nya expressed her confusion that if the Serpentine didn't take the hard-drive, who was the culprit.

Both questions had to be put on hold though, as Nindroids suddenly attacked the place, and Kai ordered the other Ninja and Nya to protect the Serpentine. The Ninja finds out that the Electrocobrai are their power source. Skales tells them at the Curse of the Golden Master is upon them, and says that they would not be able to assist the Ninja because they're choosing to stay out of the conflict. The Ninja then return to the surface.

Enter the Digiverse
In the top of the Borg Tower, Borg prepares the device that will lead the Ninja to the Digiverse, were the digital overlord was, a digital world where they will be able to gain access to the Tower's central computer and fight the Overlord directly. When Jay points out that the hard drive is still missing, Borg explains the device will "download" the Ninja themselves, along with the Techno Blades, into the computer where the Overlord dwells. He also explains that this is the only method to succeed, as it will be a matter of time before the Digital Overlord fully drains Lloyd's power.

Although apprehensive, the Ninja are "downloaded" successfully, and they wake up in the Digiverse. In no time, they begin mastering the advantages of the digital world, except for Kai. the Ninjas begin their trek down toward the Tower's central computer—ironically below the Tower, where the Overlord had been defeated years before. When the Overlord realizes they are close to him, he attempts to immobilize them, but fails due to P.I.X.A.L. electronically interfering from outside. He then turns the digitized New Ninjago City upside down, but the Ninja keep moving with their digitized vehicles. Kai almost died when he tries to jump off the digital Borg Tower because his vehicle disappeared, but gets rescued by Zane. Together they get to the top—that is, the bottom—of the tower and insert the Techno Blades only to find the Overlord severed the circuit to the motherboard.

The Ninja are severely beaten by the Overlord as he consumes more of Lloyd's golden power, proclaiming his becoming a true "golden master" of the real world and the digital world. Strengthened by Lloyd's proclamations that the Ninja always have each other's strengths to fight together, Ninjas fights off the Overlord's influence and turns gold and, using Lloyd's shared power, reroute the circuit to the motherboard and completely destroy the Overlord virus from the system, initiating a reboot.

Codename: Arcturus
At the Temple of Light, Lloyd gives up his Golden Power to restore the Ninjas' elemental powers. Meanwhile, at Borg Tower, Master Wu spots General Cryptor aboard a train heading for Ouroborus. going through a road near where Kai is.

Kai stands in a gas station flirting with a girl, when P.I.X.A.L. calls him and tells about the Nindroids approaching. He jumps into his Prototype X-1 machine car and heads to the highway. When he comes to the bridge, he accidentally fires rockets to the sky which got spotted by Pythor who was driving in a leading fuel truck with General Cryptor. He then launches Nindroid flyers to hunt him and destroy his car.

Kai successfully repels their attack, but Cryptor fires rockets at a hill above them and soon rocks that got separated from the hill fall down to his car. They block the road, but Kai and P.I.X.A.L. destroy them with rockets. To hunt down General Cryptor's truck, P.I.X.A.L. activates his interception bike which Kai is unable to control so he bumps into edge of the oil tank. He gets up to its roof and fights Nindroids, using his new fire power and Spinjitzu. This proves to be a mistake as he realizes that his fire power lit up the oil tank and that its going to explode. Soon they got to a tunnel, where the Min-Droid attacks him. The X-1 machine, remotely driven by P.I.X.A.L, accidentally scrapes an oil tank so gas starts leaking. It soon gets to flame from the sparks of p Min-Droid fighting Kai. When the fire comes to the leaking tank, the whole tank explodes but Kai jumps off to Pythor's truck and saves himself. He stays beneath his truck and hears Pythor talking to the Overlord by a radio. He tells people in Borg Industries that the Overlord is alive, but gets captured by Pythor who takes him to the lost city of Ouroboros.

By the time Zane, Cole, Jay, and Lloyd get to Ouroborus, they don't find anything new around until a huge door below them opens and they fall into an underground base where they find a huge rocket called "Arcturus." They realize that the rocket will lead Pythor and his Nindroid minions to space and reach the Golden Weapons from the star where the Mega Weapon was destroyed. Lloyd tries to stop him from lifting the rocket but Overborg stops him. With help from a freed Kai, the other Ninjas hold off the Nindroids with their new elemental powers. Pythor initiates the countdown for the rocket to launch into space, so Lloyd leads the Ninja into it just in time.

The Void
The Ninjas are in the Arcturus rocket as it flies through space. They make contact with Borg Tower and voice their concerns about their current predicament to Wu, Garmadon, Nya, and P.I.X.A.L.

The Ninja put the space suits just as the rocket disengages its unneeded engines. However when they climb up toward the door leading to the cockpit they are attacked by Nindroids, who fire on them with laser guns.

Following Jay's initiative of going commando and learning that their Spinjitzu does not work in zero-gravity, the others take the laser guns too so they successfully repel the attack. Soon the Arcturus enters an incoming comet's tail and is battered by massive ice meteorites.

The Arcturus rocket crashes on the comet's surface where the melted and fused forms of the Golden Weapons are located. The Nindroids and the hidden Ninja discover them as Jay excitedly finds an extraterrestrial beetle. Unfortunately, said bugs eat anything metal—a fact that reaches them from Nya too late. While the Nindroids get away with the golden mass aboard their ROV, the Ninja follow pursuit in their own while using the pursuing bugs against their robotic adversaries. The Ninja eventually succeed in taking Cryptor's ignition key to the rocket, so that they cannot leave the comet with the Golden Weapons and take them to the Overlord.

However, their victory is short-lived when they find another bug swarm among the rocket—chewed up in pieces. Seeing this as well, Cryptor and the other surviving Nindroids use their built-in boosters to fly off the comet with their golden prize. Stranded on the surface with the insects, the Ninja report to the others that they had failed and are not coming back home.

The Titanium Ninja
In space, the Ninja despair after repeated failed attempts to escape. However, Lloyd refuses to give up, suggesting that they use their elemental powers and everything around them to restart the ship. Heartened by Lloyd's words, the Ninja repair the ship and use Zane as a power source. Though Zane gets overheated by the strain, they manage to fly back to the Earth—to land safely, the Ninja uses a new technique: Elemental Shields.

P.I.X.A.L. uses a motorcycle to catch up with her friends, using her power to land them on their vehicles. As the Ninja reunite with their allies, Cyrus tells them that they should head for the Temple of Fortitude, a place where the Overlord and the First Spinjitzu Master battled long ago. He claims there's a shield at the place, so the Nindroids won't harm them, and there is something he wants to give them that may help them save the world.

The Ninja begin travelling to the temple, but pause when they see the Golden Master's path of destruction. Lloyd reminds his friends that the only way to save Ninjago is to reach the Temple of Fortitude, but the Overlord sees them and uses a massive Spinjitzu tornado against them. The Ninja swiftly run back, rendezvousing with Cyrus, Wu, and Garmadon. There Cyrus gives them the ultimate weapon—a pill. Borg then explains that it was no ordinary pill, it could make anyone shrink. Garmadon and Wu decides to would hit the pill straight into the Overlord's mouth. Borg gives the Ninja armor which protects them from some attacks from the Overlord.

The Ninja go into Ninjago City, when an item hurls at them but are protected since they have on the armor. Wu hits the pill, which heads straight to the Overlord's mouth, but Pythor sacrifices himself and swallows the pill instead. As a result, Pythor shrinks down to the size of a worm. The Golden Master is outraged that the Ninja try to shrink him. He obtains the Ninja with his Golden Power only to miss Zane. The Ninja of Ice tells his friends to support him one last time, and the Ninja bounce him. Although, during the process, he landed and touched the Golden Master's gold. He refused to let go, admitting the fact that Ninja never quit, which frees his friends. He remembers his past, and freezes the Overlord which also killed him and the Golden Master. The Ninja are disappointed that Zane has passed, and proceed to his funeral.

Borg makes a speech on how he thought technology was the best way to destroy problems, but instead cost more. He now names Zane the Titanium Ninja and passes the microphone to Kai. The Red Ninja claims no one knew what powered Zane, and he thought it was brotherhood, because that's how Zane powered him. Saying that Ninja never get forgotten, Kai says no matter where Zane is, he'll always be part of the team. When he finished his speech, snow began to appear.

Winds of Change
With Garmadon gone, Kai took Lloyd under his care and promised to watch over him. He and the Ninja used their Elemental Dragons to capture a Fangfish that had been terrorizing a local village, though Kai bragged that he once had caught one twice as big. Upon returning successful to Wu's new tea shop Steep Wisdom, Kai and the others were sent by their Master into Ninjago City to advertise the new store, yet without using their powers. While they obeyed their master at first, after failing to attract anyone Kai decided at use his elemental powers to create a teapot out of fire.

Unfortunately, Morro possessed Lloyd's body and the other Ninja lost their elemental abilities. They returned to Wu for answers just as the tea shop fell under attack by the Master of Wind. Kai attempted to help Lloyd regain control of his body, but was taken away by the Ninja as the fled in the Destiny's Bounty just as the Green Ninja was starting to regain control.

Ghost Story
Morro soon caught up to them using his Elemental Dragon and while the masters of earth and lightning fended him off, Kai and Zane escorted Wu to their quarters for him to make an imprint of the staff's secret message. The ghost ninja crippled the flying vessel however and soon confronted Kai who was almost thrown out of the Bounty. He was saved by Zane, but the ship crashed in the Forest of Tranquility.

The Ninja made camp and Wu told them of his past with Morro. That night Kai dreamt of him promising to look after Lloyd, only for the Green Ninja to be eaten by a Fangfish. He was awoken by a walliper to find that Misako has arrived and discovered that the first symbol means Airjitzu, a martial art created by Master Yang, though discover that Ronin had recently stolen the only known scroll. The Ninja mount wallipers and Kai leads them towards Stiix where Ronin was keeping the scroll.

Unfortunately, their head start was lost when Kai lead them away from Stiix rather than towards it. After Zane pointed this out, Jay and Cole elected to follow Zane instead and they soon came across train tracks leading to Stiix.

After nightfall, they came to a train station and stopped, intending to rest. However, they were soon beset by Wrayth on the Chain Cycle and engulfed in a frenzied battle against the ghost menace. Incidentally, he defeated himself when his chain hooked on a nearby water tower and poured its contents onto himself. The Ninja were left stunned by this, but realizing that a passing train was headed to Stiix, quickly ran after it.

Stiix and Stones
The Ninja eventually arrived in Stiix and confronted Ronin in his shop. The thief demanded a high price for the scrolls, but due to Kai's horrible negotiating skills, it was raised even higher. To earn money, the Ninja were hired to build a dock and Kai operated the crane. Unfortunately, a fly damaged the Titanium Ninja's language database and they ended up accidentally destroying the bridge. With Zane unable to speak, Jay took charge and decided that they should simply steal the scrolls.

When they did, however, Morro and his latest summoned partner Soul Archer had arrived at the shop for the scroll and summoned more ghosts. Using the Aeroblades, they got rid of the ghosts; unfortunately, Ronin called for R.E.X. and took the scroll but didn't get far thanks to Morro. Kai chased after Morro but failed to regain the scroll. In addition, Ronin offered to help Kai out of the strangle weed in exchange for something: Kai gave him everyone's business shares of Steep Wisdom. In return, Ronin told him of an alternate way to learn Airjitzu: Master Yang's Haunted Temple.

The Temple on Haunted Hill
During nightfall, the Ninja sneaked into Yang's Temple in order to retrieve the Scroll of Airjitzu. After pranking Cole, the Ninja tried to warn him that a thudding sound they heard was real. The Ninja were eventually forced to avoid all the obstacles Yang threw at them, and they decided to tie themselves together to prevent themselves from running away.

The Ninja then have to chase Morro into the attic, where Yang gave them the Scroll. After realizing the sun's almost up, the Ninja fled the Temple, but was surprised to see Cole as a Ghost.

Peak-a-Boo
Kai began complaining about his new Deepstone suit because it was heavy, which he believed prevented him and the others from performing Airjitzu. Wu told him that it would protect him from turning into a ghost. Sometime later, Soul Archer shot him in his chest, but the Master of Fire didn't turn into a ghost.

Once they were nearing the highest peak of the Wailing Alps to beat Morro from reaching the Cloud Kingdom, Kai was the first to successfully do Airjitzu up to the top. He was then able to encourage Cole by telling him ghosts can't die, which helped him perform Airjiztu and allow them to beat Morro into the Blind Man's Eye.

Kingdom Come
Upon reaching the gates of Cloud Kingdom, Kai and the other Ninja were greeted by Fenwick. They were then shown inside the writing hall where the Ninja learned that the citizens of Cloud Kingdom were the writers of destiny.

Fenwick proceeded to inform the Ninja that Morro sought the Realm Crystal hidden in the tomb to unleash The Preeminent, before ushering them into a building filled with toys to meet the "master writer." They quickly discovered it to be a trapped as they had been locked away with Nimbus, a terrifying creature. With Cole's ghost abilities, the Ninja managed to escaped and discovered that Fenwick was actually working for Morro.

The Ninja soon ran into Nobu who informed them where the Sword of Sanctuary was kept, though the Ninja arrived just after Morro claimed the sword. With it in hand, the ghost was able to escape from Cloud Kingdom though after an intense chase down the Wailing Alps, the Ninja emerged victor with the sword in possession.

The Crooked Path
When the Ninja are preparing Stepped Wisdom for a Ghost attack, Kai puts up a bucket of water on top of a door. After hearing a bell ring, Kai and the others hurled water balloons at the Postman, thinking he was a Ghost. The Postman then told them they're going out of business due to the lack of customers. They then decided not to tell Ronin so he can stay and help them.

When the Ninja were told to come in Steep Wisdom so Misako can explain the third clue, Kai asked Ronin what he's looking for, to which he said he was just sorting the tea blends. Misako and Wu told them about the three tests and that Kai reminded her earlier about a map at the back of the Scroll of Airjitzu and that the reflection on the sword just might tell them the location. They went outside to stop Ronin from stealing the sword, but was caught in the traps they had set up earlier. When they chased after him, they realized his ship was empty.

They later got a message from "Ronin" stating that the tomb was located in the Caves of Despair. They checked it out, and found the skull symbol at the entrance. They initially thought the lanterns they encountered were the first of three tests, but was proven otherwise when nothing happened. They encountered a Kethanol geyser and when Cle blocked it with a boulder, it erupted and they found themselves riding on minecarts. Before they could fall into a pit of lava, R.E.X., on autopilot, came by to save them. Ronin, on a message, said he'll let them borrow R.E.X. to travel to the real location of the tomb, under the ocean.

Grave Danger
Arriving at the tomb's entrance after nearly avoiding the Leviathan, and accidentally leaving their Aeroblades behind, the Ninja head inside and found themselves surrounded by sixteen doors, each with images on it. P.I.X.A.L. informed Zane they're in a zoetrope, and they have to use Spinjitzu to find the correct symbol. He did so, and they enter the door with the Yin-Yang symbol.

They entered the second test room, with Kai determined to reach the staff, activating most of the traps. Cole had the idea to jump down the hole they made, and after it works, he reluctantly followed suit.

Falling into the third test room, the Ninja, except Cole, saw their future in the wall's reflections. They spotted Morro, and Kai was able to trap him with stalactites. They solved the test by digging straight down and end up in the tomb.

Suddenly, Morro, who managed to escape Kai's trap, threatened to kill Lloyd if they don't give him the Crystal. The Ninja realized they have their powers back, but it's weak. Kai secretly burned the Crystal, Making Morro drop it into a nearby river. Lloyd attacked him, but Morro pushed him down the river, with Kai and Cole trying to save him. With Cole not being able to touch water, Kai dove in to save him, however, he was not able to grab the Crystal in time, resulting in Morro winning. When they got out of the tmb, Kai comforted Lloyd that they'll grow stronger as he recovers.

Curseworld, Part I
Kai and the rest of the Ninja went to Steep Wisdom to get vehicles Cyrus built. Unfortunately, Kai only got a headband due to the lack of time. Kai suggests they use Nya as the key to get close to the Ghosts, to which she agrees.

Trying to distract the Ghosts, Kai poured tea on one of them, getting them to chase him. Eventually, he tries to stop Lloyd from listening to Morro when he's trying to destroy the Crystal, but failed. The Ninja were forced to watch Lloyd get captured into the Cursed Realm.

Curseworld, Part II
Kai tried to weaken the Preeminent by using his Fire, but she didn't budge. When Cole was about to use his Blaster Bike on the Preeminent, the Ninja kept shooting their powers at her to cover him.

Kai suggests they get closer to the Preeminent to save Lloyd, but it was no use. They have to go back to the ship. They see Lloyd come back, and had to destroy the stilts to drop the Preeminent into the sea, after which the Ghosts defended her with houses. He went closer to the Preeminent, allowing the Ninja to follow suite.

He fell into the water, but Zane told him to use his Fire on Soul Archer and together with his Ice, they were able to make water to defeat him. However, the Ghost respawned, much to their disappointment. They went back to the ship in order to defend its passengers. He watched as Nya destroy the Preeminent with her unlocked True Potential.

Dark Island Trilogy, Part 1
Kai and the other Ninja were summoned to the Samurai X Cave by Master Wu, who informed them that Misako and Ronin had gone missing off the coast of the Dark Island. The Ninja quickly readied the Destiny's Bounty and they set off towards the island.

Upon nearing the island however, the Bounty encountered an unnatural storm that sent the Ninja falling from the sky. When Kai awoke, he found himself alone in the middle of a vast desert.

Day of the Departed
Using their new vehicles—including the components of the Ultra Stealth Raider—the Ninja traveled to the Ninjago Museum of History on the Day of the Departed in order to acquire lanterns for the celebration. After viewing the Hall of Villainy, the Ninja split up to pay their respective requests, inadvertently leaving Cole behind. Kai and Nya traveled back to Four Weapons Blacksmith in order to commemorate their parents, and Nya questioned whether they would ever learn what really became of them. Master Chen and two of his Anacondrai Cultists, revived by the dark magic of Master Yang, then arrived to attack the pair, but they were able to defeat the villains and destroy them. Returning to the museum, they found their friends and learned they went through similar experiences, wondering what the cause was before Wu and Morro arrive telling them it was Yang's plan.

Seeing Morro, Kai and the Ninja armed themselves as Jay question how many other ghosts there were left with Kai stating they've stopped several others and what's one more. He is surprised when Wu tells them that Morro was there to help and the latter tells them that Yang tricked Cole into opening a rift to return to Ninjago. The Ninja soon realized they forgot about Cole and Wu orders them to ready the Bounty and head for the Temple of Airjitzu while a redeemed Morro returns to the Departed Realm.

The Ninja used the Bounty to travel to Yang's floating Temple of Airjitzu, where they are caught in a powerful storm with wind blowing their ship around. However, their timely arrival gave Cole the drive needed to win and they watch as he overpowered Yang.

Kai and the others become confused by Cole speaking to Yang telling him he needed to pass through the Rift.

The Ninja watched as the Rift closes before getting caught in its shockwave, forcing them to make a crash landing on the ground of the floating Temple. Once they landed, they feared if Cole hadn't made it through the Rift in time but were overjoyed when he emerged from behind a rock human again. The Ninja happily hugged their friend, relieved to have him back to normal. Kai soon pointed out the restored Temple of Airjitzu and at Cole's suggestion, they make it their new base.

Later that night, they gathered around a fire with their families and friends listening to Cole's story before releasing lanterns into the sky in celebration.

Dead Man's Squall
As they were discussing the map wrapped around the baby's blanket, Jay, who is trying to get the last meatball, accidentally stabs Kai's hand with the fork.

The Quiet One
As they tried to fix the Bounty, the baby, who had a growth spurt, hands Jay a pair of pliers, surprising Kai and the others. Kai is shocked to see the baby drink tea, before the child said their motto: "Ninja never quit," after Jay stated he quitted. This makes them realize the baby is a regressed Master Wu, which shocks them.

The Ninja tell Nya the things the baby did and how they discovered he is Wu, she doesn't believe them until she hears the baby talk. Afterwards, questions are raised by how Wu reverted to a toddler; Nya brings up Wu being touched by the Reversal Blade before he was lost in time. Kai questions his sister who states that it could of caused him to de-age. Kai listens as Zane states if Nya is correct, the blades' effects have worn off and now Wu will keep aging until he returns to normal, eventually.

The Ninja later discover Harumi is the Quiet One as the Sons of Garmadon attacked and surrounded them.

Firstbourne
Marooned in the Realm of Oni and Dragons, the Ninja spend a full week in the realm trying to gather supplies. Kai is the most worked up over the situation, as seen when he criticizes Jay for not freaking out and states him being calm is unsettling to him. Kai and Zane spend most of their time building a radio in the hopes of communicating with the realm of Ninjago.

As Kai and Zane listen on the makeshift radio, they see that Jay has completely lost his grip on reality as he plays on his homemade game, which is really a piece of wood. After Zane tells them he has intercepted a transmission, they believe it's from Ninjago, however, the people on the other side state they are preparing something. Kai doesn't understand some phrases they uses and Zane translates them to him by stating that they are talking about an ambush. Hearing this, Kai realizes they are talking about them and tells the others to run away.

As the trio run, Kai makes sure to keep a look out for the attackers before figures in the fog quickly grab each of the Ninja in chains and drag them off.

Held captive, Kai and the others are brought, blindfolded, into the lair of the Dragon Hunters and meet the Iron Baron.

Iron & Stone
As they are held captive, Kai sees the Baron's throne (made from bones of the Ultra Dragon) and states he already hates him. When they were questioned over who else was with them, Zane tries to deny it, but Jet Jack shows them one of Wu's diapers. Kai spoke up by trying to pass them off as being Jay's as he tried to lie, saying he has a weak bladder, but they don't believe them. Iron Baron accuses them of being Oni while ignoring Kai's protests.

The captured Ninja are taken into The Pit which Jay notes is an arena where they will be attacked by something. Kai and Zane note Jay is still not in his right mind and is useless in their plight. They find they are to fight a Dragon and are told by a hunter named Chew Toy to play dead.

During the fight, Kai goes through with playing dead and the Dragon, Slab, smells him but doesn't attack. Cole and Wu get their attention and use a lever to put a chain for them to trap the Dragon. Kai then alerts Jay that the Dragon would attack him but Zane freezes it, exposing their Elemental Power to all. Iron Baron realizes his mistake of thinking they were Oni and orders his followers to hunt them as Kai tells his friends to prepare for a brawl as the Hunters surround them.

Radio Free Ninjago
Kai, Jay, and Zane are cornered by the Dragon Hunters and have no choice but to use their Elemental Power. Kai does an estimate on the foes before Zane corrects him on the exact number and he states Zane was better at counting. Kai asks Jay if he's all right, as Jay lists all of the events that have befallen him and has a breakdown; this display causes Zane to note to Kai that he is back to normal.

They use their Elemental Power to fend of the Hunters, when Heavy Metal jumps down with the Dragonbone Blade. They try to use their power on him, but as Zane points out, the blade attracts their Elemental Power. Now unable to use their power, they are chained up by Heavy Metal, and put in the back of the Dieselnaut.

Held in place by the Hunters with Vengestone, Iron Baron approaches them and admits his surprise at them not being Oni, but trained in the ways of the First Spinjitzu Master. Kai is shocked by his familiarity and asks if he knew him as Baron states he knows his legends and calls him the coward who ran away to Ninjago. Kai then asks if he knows how to get them back, to which Baron responds no, but he had no interest of helping them anyway. He then declares they are hunting Dragons and hopes that the catch he makes will be good.

He then turns on the machine and it releases a strange energy that triggers elemental reaction and the Ninja are subjected to a device which draws out their Elemental Power. Jay realizes that the Hunters are using them as a bait since their powers attract the Dragons while noting it tickles.

Soon after, a Wind Dragon is attracted to the Ninja. Meanwhile, Cole and Wu (who are disguised as Hunters) "accidentally" knock the other Ninja off the stand. They try to rescue them, but the Ninja are immediately put back into the back of the Dieselnaut by Daddy No Legs.

Now in the back of the vehicle, they are forced to sit back and watch as the Hunters reel in and eventually capture the Wind Dragon.

Cole promises to figure a way out of this situation for them, and the Dragons.

How to Build a Dragon
As he and his friends are caged by the Hunters, Kai sleeps before Jay wakes him up by telling them he heard Lloyd's voice on the Hunters' radio and Kai questioned him if he has lost it again but after he explains they see he is still sane.

As the Ninja are forced to work, they wonder on what to do as Jay suggests building a Dragon and they call it out foolish but he tells them of his plan to trick Baron into thinking Firstbourne was attacking so they and the Dragons can escape. The ninja like his plan and get to work by secretly gathering supplies.

The Gilded Path
The Ninja found a camp spot and sat around the fire before Wu woke up and they see that he has aged again and become a teenager over night. When Jay commented it was bad, Kai mentioned they were teenagers and Jay called them "grown-up" teenagers.

Heavy Metal then finds the Ninjas' camp and makes her presence known, Heavy Metal threatens the Ninja with her weapon telling them they are her prisoners now before interrogating them on Wu truly being the son of the First Spinjitzu Master. Kai tells Wu not to reveal his heritage since it might be dangerous like their power but Metal fires an arrow at Cole after stating they heard Kai's mumbling. Kai watched as Wu revealed himself and Metal revealing themselves to be a woman named Faith who is on their side.

The Weakest Link
Kai and Jay fight over the water pouch until Faith cuts a cactus and they drink the water as she criticizes them. Kai and the others are taught by her to use chain guns to survive against the Dragons.

The Ninja dealt with the attack of Hunters and were soon able to hijack the Dieselnaut and escape but at the cost of Faith, who was captured by Baron.

Saving Faith
At Wu's pleas, the Ninja go to rescue Faith from the Hunters. She berates them and warns them it was trap but the Dragon Hunters appear and capture them.

Kai is later tied to a stand with Cole and Zane, Kai shares banter with the others to keep their spirits up. He explains to Wu of why this is important and they share a laugh. He watches as Faith tells the other Hunters that Iron Baron lied to them about the Oni who have been gone from the realm for centuries and tells them that he possibly killed the Hunters to get Dragonbone Blade. After Iron Baron silences any growing rebellion by asking threatening them, an annoyed Baron hushes his prisoners by turning on the elemental device.

However, the torture causes Wu to regain all of his memories and slightly aged further into an adult. Kai watches as Wu breaks free of his bonds and begins to fight Wu with the Dragon Hunters but is knocked aside. He watches as Iron Baron negotiates with Wu who accepts the offer of leading him to the armor to return to Ninjago. Kai, Faith, and the Ninja tell him not to help Baron but he tells them to believe in him.

Kai is left to watch as Wu and Baron leave the area in search of the armor.

Lessons for a Master
Kai and the others were still stuck on the wooden stakes. Above them, two vulture-like birds fly above them, and Kai asks if they are Zane's falcon. However, Zane remarks that his data picks up that they are a group of avian scavengers, that will pick them apart upon their demise. Faith confirms this, and Jay freaks out.

They notice that the other Hunters are arguing down below. While they're distracted, they try to rock their bodies side to side in order to knock the stakes over. The rocking seems to be working, and they cheer. As they do, Jet Jack asks them what they're doing, and she cuts them down.

After the Ninja are freed, they are skeptical of the Hunters' intentions and Kai tells them if they plan on eating them to eat Cole first since he is filled with cake as his friends are shocked by this. However, the Hunters reveal they want the Ninja to defeat Baron as they see Baron was only using them and will become even more dangerous with the armor.

They arrive at a bridge that leads to the armor, and find that it's too late, as the bridge has fallen.

Kai and the others return from the bridge to give the bad news to the other Hunters, and just then, Wu rides back the Firstbourne out of the nest without any chains, and discovers the Ninja, Faith, and the other Dragon Hunters, who had since turned on Baron in his absence and freed the Ninja.

As soon as he lands, he reveals Iron Baron's fate. The Ninja bow to him as Dragon Master, but Wu claims that it is he who should bow to them, as it was they who taught him everything since they arrived in the realm. Kai watches as Cole points out that their job isn't finished, Wu asks the Firstbourne if she will get him and his former students home. She agrees to do so, calling upon four other Dragons for the Ninja to ride. Kai gains a new Fire Dragon and is amazed at it.

With their work finally finished in the Realm of Oni and Dragons, Kai and the others ride the Dragons out of the realm, and begin their return to Ninjago.

Green Destiny
Arriving in Ninjago through a portal forming in the air, Kai and the others are devastated by the city's state and start to look for their friends. They don't have to search for long as Nya contacts Kai and he is happy to hear his sister's voice and they make it in time to save them from Ultra Violet and her lackeys who flee after seeing the dragons. Kai then reunites with his other friends who are happy that he and the others are back however, Kai sees Skylor and learns from Lloyd that she was poisoned by Garmadon's power.

The Ninja continue fighting against the Colossus, using Vengestone Harpoons to try and incapacitate it. However, the chains are ineffective, and they eventually run out of them. Kai jumps onto the Colossus and begins binding the chains together even tighter.

The Ninja soon run out of chains and wonder what to do, before Firstbourne returns and Wu fires his chain gun at the behemoth. The tides continue to turn in the ninja's favor as their allies return to the city to help defeat the Colossus. Very soon, the Ninja and their allies incapacitate the Colossus using the chains, and it falls to the ground. Once Garmadon loses his power, the Colossus crumbles apart and the ninja are victorious. In Nya's armored van, Kai tends to Skylor who wakes up after her health is restored, assuring her they have won the battle.

They then have the Sons of Garmadon arrested before Lloyd arrives with his defeated father and the ninja celebrate his restored power while Garmadon is arrested.

Several days later, the Ninja clean up the Royal Palace and complain since they saved the city before Wu tells them there's trouble.

The Ninja run out of the palace and find a crowd celebrating their victory. During this time, Kai and Skylor hug becoming a couple.

Appearance
Typically preferring red attire, Kai has tall, thick spiky reddish-brown hair, shaped like fire. He is often seen with a focused expression on his face, with a scar visible on his right eyebrow and bandage above his left. Before Season 8, his eyebrows were black, his bangs parted to the right and instead of a scar, he had a notch on his left eyebrow.

In "Way of the Ninja," Kai wore a white shirt and red pants as well as an orange apron. Since "The Royal Blacksmiths," Kai's civilian attire consists of a red half zipped up sweater over a maroon shirt with his symbol on the chest and brown pants. Throughout Season 6, he wore a red cap over his hair to conceal his identity. In the pilot and The New Masters of Spinjitzu, it can be observed that Kai has chest hair while wearing pajamas, but in later appearances where his chest is visible, including the appearance of his past self while time travelling to the events of the pilot, the hair is no longer there.

For more images on Kai's appearance in his different Ninja suits, click here.

Age
Like the majority of his fellow Ninja, Kai is currently in his late teens. However, the Ninja do not officially have specific ages, as they are meant to be perpetually in their teenage years for the duration of the show.

Potential Estimations: During the events of the pilot and Season 1, he may have been at least 16 years of age. As the most recent events take place three to four years after the events of Season 2, he could possibly be around 19.

Personality
Fittingly for his elemental affinity, Kai is very hotheaded, prone to taking action before he thinks things through. He is capable of making careful observations when the need arises, but his emotions often override his caution. His single-mindedness made interaction with his teammates difficult at first (especially due to his worry about Nya), but he eventually learned to work with the other Ninja. He can be very cocky at times, sometimes even to the point of selfishness, insisting that he is better than others, gloating about his victory, or yelling about his failures.

Later, following the Ninjas' fame, Kai would end up getting something of a larger head and bigger ego, constantly flirting with girls and enjoying the merchandise styled after him. Likewise, he indulged in his fame the most out of all of the Ninja.

Kai also has something of an overconfident stubborn side, believing that he is in the right until overwhelming evidence to the contrary is presented. This is especially pronounced during Lord Garmadon's stay on the Destiny's Bounty; Kai repeatedly accused the four-armed villain of treachery or plotting despite Garmadon's insistence that saving Lloyd was his primary concern at the time. On the other hand, Kai's stubborn streak lends him incredible determination that allows him to bolster the team's spirit in the face of impossible odds.

The most prevalent facet of Kai's personality is his good heart and dedication to people he cares about—if someone can earn his friendship, he will stop at nothing to protect them. Much of his stubbornness and recklessness are due to his desire to help his loved ones, either directly or by becoming strong enough to defeat anyone who might threaten them with their plans. In turn, his friends and family work to balance out Kai's more extreme traits, causing him to become a levelheaded mentor for Lloyd by the time he and his comrades begin training the Green Ninja. According to Zane, Kai's desire to protect his friends is just as powerful as his temper.

In the Tournament App
Kai is a playable character in the Tournament App. His teacher version can be purchased for 50,000 studs, his jungle version can be purchase for 250,000 studs, and his special move is Spinjitzu, much like Jay, Cole, Zane, Master Wu, and Master Garmadon.

Weapons
Kai favors swords in combat, taking up a curved silver blade against the Skulkin when they attacked his shop. He used the Sword of Fire as his primary weapon until it was lost, and then switched to wielding regular katanas. He eventually gained an Elemental Blade that allowed him to harness his fire abilities to an even greater degree. Months after Lloyd defeated the Overlord, Kai, along with the other three Ninja (Cole, Jay, and Zane), receive Techno Blades, a weapon which allows the Ninja to hack into any electronics. He also has an Aeroblade (along with Cole, Jay and Zane), that can destroy ghosts.

Rebooted
''Kai is the ninja of Fire, and though he is a hero now, he came from humble beginnings. His father was a trusted ally of Sensei Wu and the two adventured together for many years. Wu would later hide the map showing the locations of the Four Weapons of Spinjitzu in his friend’s blacksmith shop. Kai was the last member recruited for the team by Sensei Wu and the last to achieve his full potential (which happened when he saved Lloyd from the belly of an active volcano!) He can be hot-headed and impatient, but is trying to control that.''
 * For the first two months of his life his parents called him Ash.
 * Kai once by accident forged a weapon called a 'Swingana' … Part yo-yo, part sword. It was not a big success.
 * When Kai uses his elemental power in a vehicle, it gets powered up and engulfed in flames … which is why flying a hang glider is a bad idea.
 * Once Kai singed off his eyebrows with the sword of fire, but no one noticed because he painted it back on with a black marker.
 * When Kai's sister, Nya, was a baby, he used to juggle hammers to entertain her. When he dropped one on his foot, she laughed the hardest.

Pilot (2017 Museum gallery)
''Kai’s impulsive personality, fierce temper and immense drive mirror the fire within him. His strong sense of justice makes him stubborn and he’ll stop at nothing if he has put his mind to it … but this is also the source of his bravery. As older brother to Nya, he is overprotective of her. While Kai’s self-confidence can be overwhelming to some people, this makes him one of the leaders and big personalities in the group.''

''Kai is the last young ninja to join Master Wu’s ninja training. His impatience with training is significant, as Lord Garmadon has kidnapped his sister. However, while he quickly becomes a skillful warrior and is the first to tame his dragon, he discovers that impatience is the enemy of a great ninja…''

Season 1 (2017 Museum gallery)
''When the prophecy of the Green Ninja is revealed, Kai is absolutely convinced that he will be the Chosen One and defeat Lord Garmadon in the final battle. In the end, Kai has to put his ego to one side. He discovers that life has a different plan for him and there are more important things than being the best. When the prophecy of the Green Ninja is revealed, Kai is absolutely convinced that he will be the Chosen One and defeat Lord Garmadon in the final battle. In the end, Kai has to put his ego to one side. He discovers that life has a different plan for him and there are more important things than being the best.''

Season 2 (2017 Museum gallery)
''Once the self-centered rogue, Kai becomes the ultimate team player. He humbly and proudly accepts his role as Lloyd’s mentor, helping the Green Ninja find his true potential. Finally he becomes the hero he’s always wanted to be, willing to give up his own life for the team.''

Season 3 (2017 Museum gallery)
''Kai feels a little like the world has passed him by. While everyone else is going high-tech, he can’t even use a toaster without setting off fire alarms. He feels like machinery is out to get him, but as time goes on during this adventure, he learns to find a balance between the past and the future.''

Season 4 (2017 Museum gallery)
''Kai is competitive by nature and Master Chen plans to use that against him. Kai’s always been second to the Green Ninja, but maybe this tournament is his chance to prove how good he really is. Is Kai willing to leave his team behind, only to get ahead? What could compel him to follow his ego...a potential love interest, perhaps?''

Season 5 (2017 Museum gallery)
''After the loss of Garmadon, Kai made a solemn promise to look after Lloyd, just as Nya cared for him when their parents passed away. So when Lloyd is possessed, Kai takes it very personally! He feels he has to save him single-handedly, but really he needs the whole team. They all have weaknesses, but their individual strengths come together to win the day.''

Season 6 (2017 Museum gallery)
''Kai loves being a celebrity. He loves being an action figure, he loves the screams of the fans, and all this crazy ninja stuff is kind of getting in the way. He’s not ready for the threat of Nadakhan or to confront his own past, which endangers the team. Like the other ninja he is given three wishes by the Djinn which don’t go to plan. He ends up trapping himself in Nadakhan’s Djinn Blade and only escapes in time to crash Nya’s wedding.''

Season 7 (2017 Museum gallery)
''Kai has long wondered what happened to his parents, who disappeared when he was a child. All he knew is that they were Elemental Masters, which is why he is devastated when Krux tells him his parents helped the Hands of Time betray Wu and the Elemental Alliance. Always a fighter for justice, Kai now fears he is destined to follow in his mother and father’s traitorous footsteps, and his quest for the truth ultimately leads to an angry confrontation with his father, Ray. Fortunately, Kai learns that Krux had lied, and Kai (and Nya) save Ray from the effects of a Time Punch.''

Season 8
''Kai’s impulsive personality, fierce temper and immense drive mirror the fire within him. His strong sense of justice makes him stubborn and he’ll stop at nothing if he has put his mind to it … but this is also the source of his bravery. As older brother to Nya, he is overprotective of her. While Kai’s self-confidence can be overwhelming to some people, this makes him one of the leaders and big personalities in the group.''

Appearances
{{Scroll|
 * 30083 Dragon Fight
 * 2111 Kai
 * 2258 Ninja Ambush
 * 2505 Garmadon's Dark Fortress
 * 2508 Blacksmith Shop
 * 853097 Kai Key Chain
 * 5000135 Kai Minifigure Clock
 * 9456 Spinner Battle Arena (Kendo)
 * 9558 Training Set (Kendo)
 * 2254 Mountain Shrine (DX)
 * 2507 Fire Temple (DX)
 * 2518 Nuckal's ATV (DX)
 * 9441 Kai's Blade Cycle (ZX)
 * 9443 Rattlecopter (ZX)
 * 9449 Ultra Sonic Raider (ZX)
 * 9561 Kai ZX (ZX)
 * 853401 Kai ZX Key Chain (ZX)
 * 9006784 Kai ZX Minifigure Clock (ZX)
 * 9591 Weapon Pack (NRG)
 * 70500 Kai's Fire Mech (Elemental)
 * 70600 Ninja Bike Chase (Airjitzu, Version 2, no shoulder pad)
 * 70605 Misfortune's Keep (Airjitzu, Version 2)
 * 70621 The Vermillion Attack (Fusion)
 * 70627 Dragon's Forge (Fusion)
 * 70633 Kai Spinjitzu Master (Spinner robes)
 * 70638 Katana V11
 * 70647 Kai - Dragon Master
 * 70650 Destiny's Wing
 * 70653 Firstbourne
 * 70655 The Dragon Pit
 * 70721 Kai Fighter (Techno)
 * 70727 X-1 Ninja Charger (Techno)
 * 3856 Ninjago (Micro Figure)
 * 70752 Jungle Trap (Tournament)
 * 70756 Dojo Showdown (Tournament)
 * 70750 Ninja DB X (Jungle)
 * 70745 Anacondrai Crusher (Jungle)
 * 70732 City of Stiix (Deepstone)
 * 70735 Ronin R.E.X. (Deepstone)
 * 70736 Attack of the Morro Dragon (Deepstone)
 * 70739 Airjitzu Kai Flyer (Airjitzu)

Pilot Episodes

 * 1. "Way of the Ninja"
 * 2. "The Golden Weapon"
 * 3. "King of Shadows"
 * 4. "Weapons of Destiny"

Mini-Movies

 * 2. "Flight of the Dragon Ninja"
 * 3. "The New Masters of Spinjitzu"
 * 5. "Return to the Fire Temple"

Season 1: Rise of the Snakes

 * 1. "Rise of the Snakes"
 * 2. "Home"
 * 3. "Snakebit"
 * 4. "Never Trust a Snake"
 * 5. "Can of Worms"
 * 6. "The Snake King"
 * 7. "Tick Tock"
 * 8. "Once Bitten, Twice Shy"
 * 9. "The Royal Blacksmiths"
 * 10. "The Green Ninja"
 * 11. "All of Nothing"
 * 12. "The Rise of the Great Devourer"
 * 13. "Day of the Great Devourer"

Season 2: Legacy of the Green Ninja

 * 14. "Darkness Shall Rise"
 * 15. "Pirates Vs. Ninja"
 * 16. "Double Trouble"
 * 17. "Ninjaball Run"
 * 18. "Child's Play"
 * 19. "Wrong Place, Wrong Time"
 * 20. "The Stone Army"
 * 21. "The Day Ninjago Stood Still"
 * 22. "The Last Voyage"
 * 23. "Island of Darkness"
 * 24. "The Last Hope"
 * 25. "Return of the Overlord"
 * 26. "Rise of the Spinjitzu Master"

Season 3: Rebooted

 * 27. "The Surge"
 * 28. "The Art of the Silent Fist"
 * 29. "Blackout"
 * 30. "The Curse of the Golden Master"
 * 31. "Enter the Digiverse"
 * 32. "Codename: Arcturus"
 * 33. "The Void"
 * 34. "The Titanium Ninja"

Season 4: The Tournament of Elements

 * 35. "The Invitation"
 * 36. "Only One Can Remain"
 * 37. "Versus"
 * 38. "Ninja Roll"
 * 39. "Spy for a Spy"
 * 40. "Spellbound"
 * 41. "The Forgotten Element"
 * 42. "The Day of the Dragon"
 * 43. "The Greatest Fear of All"
 * 44. "The Corridor of Elders"

Season 5: Possession

 * 45. "Winds of Change"
 * 46. "Ghost Story"
 * 47. "Stiix and Stones"
 * 48. "The Temple on Haunted Hill"
 * 49. "Peak-a-Boo"
 * 50. "Kingdom Come"
 * 51. "The Crooked Path"
 * 52. "Grave Danger"
 * 53. "Curseworld, Part I"
 * 54. "Curseworld, Part II"

Season 6: Skybound

 * 55. "Infamous"
 * 56. "Public Enemy Number One"
 * 57. "Enkrypted
 * 58. "Misfortune Rising"
 * 63. "Operation Land Ho!"
 * 64. "The Way Back"

Day of the Departed

 * "Day of the Departed"

Season 7: The Hands of Time

 * 65. "The Hands of Time"
 * 66. "The Hatching"
 * 67. "A Time of Traitors"
 * 68. "Scavengers"
 * 69. "A Line in the Sand"
 * 70. "The Attack"
 * 71. "Secrets Discovered"
 * 72. "Pause and Effect"
 * 73. "Out of the Fire and Into the Boiling Sea"
 * 74. "Lost in Time"

Season 8: Sons of Garmadon

 * 75. "The Mask of Deception"
 * 76. "The Jade Princess"
 * 77. "The Oni and the Dragon"
 * 78. "Snake Jaguar"
 * 79. "Dead Man's Squall"
 * 80. "The Quiet One"
 * 81. "Game of Masks"
 * 82. "Dread on Arrival"
 * 83. "True Potential"
 * 84. "Big Trouble, Little Ninjago"

Season 9: Hunted

 * 85. "Firstbourne"
 * 86. "Iron & Stone"
 * 87. "Radio Free Ninjago"
 * 88. "How to Build a Dragon"
 * 89. "The Gilded Path"
 * 90. "Two Lies, One Truth"
 * 91. "The Weakest Link"
 * 92. "Saving Faith"
 * 93. "Lessons for a Master"
 * 94. "Green Destiny"

Dark Island Trilogy

 * "Dark Island Trilogy, Part 1"
 * "Dark Island Trilogy, Part 3"

Video Games

 * LEGO Battles: Ninjago (non-canon)
 * LEGO Ninjago: Nindroids (non-canon)
 * LEGO Ninjago: The Final Battle (non-canon)
 * LEGO Ninjago: REBOOTED Game (non-canon)
 * LEGO Ninjago: Tournament (non-canon)
 * Ninjago Rush (non-canon)
 * LEGO Ninjago: Shadow of Ronin (non-canon)
 * LEGO Dimensions (non-canon)
 * Rise of the Nindroids (non-canon)
 * Ninja Code (non-canon)
 * Legendary Ninja Battles (non-canon)
 * Fallen Ninja (non-canon)

Books

 * A Team Divided (non-canon)
 * The Search for Zane (non-canon)
 * Breakout! (non-canon)

Graphic Novels

 * LEGO Ninjago: Ghost Ninja (non-canon)}}