The Sword of Fire was one of the four Golden Weapons used by the First Spinjitzu Master to create the realm of Ninjago. After forging the island, the weapons were passed onto his sons, Wu and Garmadon, who were to keep them safe. Yet when Garmadon was corrupted by the Great Devourer, he tried stealing the weapons, using the sword and the Nunchucks of Lightning to fight his brother. Wu was forced to defeat his brother and condemn him to the Underworld, after which he hid the Golden Weapons.
Many years later, Wu trained four Ninja and sent them off to claim the weapons. Kai, the master of Fire, claimed the sword and protected it from Lord Garmadon. When Samukai wielded the four Golden Weapons simultaneously, he was disintegrated, creating a portal that allowed Garmadon to escape the Underworld. The Ninja would wield the Golden Weapons in their battles against the Serpentine, but they eventually gave the weapons to Lord Garmadon in a bid to kill the Great Devourer. Using the Golden Weapons, Garmadon slayed the beast, but took off and forged them into the Mega Weapon, which the Ninja eventually destroyed and shot off into space. The fused weapons wound up on a star known as Arcturus.
Towards the end of the Nindroid Conflict, the Overlord sent Cryptor and several Nindroids to Arcturus, where they claimed the remnants of the Golden Weapons. Despite their efforts, the Ninja failed to stop the Nindroids from escaping with the fused weapons, which they melted down and turned into the Golden Armor. The armor was worn by the Golden Master, the Overlord's god-like form, as he wreaked havoc on Ninjago using the Ultimate Weapon, parts of which were also built using the Golden Weapons. During the climactic standoff at Borg Tower, Zane sacrificed himself and grabbed hold of the Golden Master's harnesses, which were molded from the Golden Weapons. While being overwhelmed with power, Zane froze the Golden Master, destroying both of their physical forms in the process.
The Golden Armor was stored away by Cyrus Borg for safekeeping, as Wu had done so many years earlier.
The Sword of Fire is able to engulf its blade in flames and shoot fireballs at enemies or objects. It can also transform into the Blade Cycle if the wielder can maintain their focus.
When the First Spinjitzu Master passed on, he entrusted the weapons to his two sons, Garmadon and Wu. However, Garmadon attempted to steal the weapons for his own selfish needs, forcing Wu to confront him before he could get away. After Wu defeated his brother and banished him to the Underworld, he hid the weapons.
When Master Wu's four Ninja proteges, Kai, Cole, Zane, and Jay were searching for the Sword of Fire, they decided to rest in the Forest of Tranquility after having found the other three weapons. In the middle of the night, Kai wakes up to see Nya standing nearby calling for him, which lures him to the Fire Temple.
Upon reaching the Temple, Nya is revealed to be Lord Garmadon's shadow in disguise, Lord Garmadon showed Kai the real Nya suspended by a chain over the lava. He tells Kai that the only way to save her is to cut the chain with the Sword of Fire, and despite knowing that he is playing into Lord Garmadon's trap, Kai pulled the sword out of its pedestal and saved Nya.
Kai is then faced with several shadow versions of himself, and while trying to fight back he realized that he cannot make any contact with them. Master Wu appeared using his own shadow to fight off the others.
Lord Garmadon awakened the Fire Dragon, and Master Wu departs to the Underworld in an attempt to keep the Golden Weapon from his brother.
Master Wu woke up in the Underworld after passing out during his journey. He then decided to go search for Lord Garmadon.
Master Wu found Lord Garmadon, who commanded Samukai to attack him. The Ninja arrived during Master Wu's battle, losing shortly after. Samukai wielded all four Golden Weapons at once, however, due to the power of the weapons being too much for him to handle all at once, he disintegrated and created a portal for Lord Garmadon to escape through.
In Defense of Ninjago
After Lord Garmadon escaped from the Underworld, each Ninja took up the weapon corresponding to their element, leaving Kai is possession of the Sword of Fire. The Fire Dragon, Flame, continued to guard it by becoming Kai's mount and pet.
During a three hour video gaming marathon with the other Ninja, Kai carelessly left the Sword of Fire on the floor, slowly burning a discarded slice of pizza on the floor.
Kai used the Sword of Fire during the tournament to determine who would be the Green Ninja, but during the fight he lost control of the sword's power resulting in flames spreading everywhere.
The Overlord's Ultimate Weapon
The Nindroids succeed getting the Weapons of Spinjitzu and have burnt them into the Overlord's ultimate weapon. Later, the Golden Master starts to destroy New Ninjago City with his newly formed mech—made out of the gold from the Weapons of Spinjitzu. However, the Nindroids were not the only ones to escape; the Ninja have used their Elemental Shields, and have traveled out of space. The Golden Master gets frustrated, and plans to defeat the Ninja. He now preforms his own Spinjitzu, trying to stop the Ninja from going into the Temple of Fortitude. He, however, fails. The Heroes of Ninjago put on armor to resist the Golden Power from him. He, somehow, grabs all the Ninja except Zane. The White Ninja eventually destroys himself and the Overlord.
- In some sets, it is called the "Golden Dragon Sword," as the piece was also used to represent the Golden Ninja's sword.
- This was the last Golden Weapon of Spinjitzu to be collected by the Ninja.
- In LEGO Universe, the Sword of Fire was simply a pair of Golden Katanas, similar to the Nunchucks of Lightning being in a set of two weapons as well.
- It is the only Golden Weapon to have an identical appearance in the LEGO playsets and the show.
- In the first wave of LEGO Ninjago sets, the Sword of Fire was represented simply as a Golden Katana.
- In Nindroids, Lloyd's Gold Ninja variant wields the Sword of Fire.
- It is the Golden Weapon that appears in the most sets.