Realm of Oni and Dragons

The Realm of Oni and Dragons is one of the Sixteen Realms. It appears to be a sandy place, and is the very first realm in existence. It is where the First Spinjitzu Master originated from, before he fled to create Ninjago.

Distant Past
The first of all of the Sixteen Realms, in this world there lived two species of beings: the Oni and the Dragons. The Dragons had power over creation, and the Oni had power over destruction. Effectively being polar opposites, a seemingly never-ending conflict between the two kinds was sparked that would go on for ages. One day, a child with the powers of both sides was born, who understood the necessity of the roles both the Oni and Dragons played in the balance. But instead of ending the war, they simply fought for control over him in order to win their sides of the battle. Torn between both worlds, the child abandoned his home to start anew. The child went on to become the First Spinjitzu Master, and with his powers, he created the world of Ninjago. By doing this, Firstbourne was left to guard the Dragon Armor and faithfully waited for him to return to the realm.

Sometime later, the Oni left this realm and headed to parts unknown. This was discovered by Iron Baron, who withheld this fact from the Dragon Hunters to rule over them.

Big Trouble, Little Ninjago
After using Traveler's Tea given to them by Mistaké, Kai, Jay, Zane, Cole, and Wu end up in a desolate, sandy island, their Ninja uniforms were ruined and part of the Destiny's Bounty behind them. When they look over their surroundings, they see dragons and realized they have been transported to the First Realm.

Firstbourne
While Kai, Zane, and Jay stayed with the Bounty to fix the radio, Cole and Wu went to look for food.

However, the ninja at the ship overheard talk about an ambush on the radio and tried to leave but were captured by the Dragon Hunters. Wu and Cole discover the situation before finding the tracks, which they decide to follow to locate their friends.

Iron & Stone
In the realm, the captive Ninja are taken to Dead's End where they are thrown into the Pit to fight dragon Slab. Cole and Wu, who were disguised as Hunters, helped them but Zane revealed he has Ice powers in order to stop Slab from attacking Jay.

Iron Baron realize they aren't Oni since they don't have Elemental Powers and ordered his Hunters to capture them since he realize they're Elemental Masters.

Radio Free Ninjago
The Marooned Ninja, except for Cole and Wu, are captured by the Hunters and are used as bait to lure Dragons. They eventually caught the Wind Dragon.

How to Build a Dragon
When the Ninja made it back to Dead's End, they planned to build Firstbourne as a distraction so they could escape.

When the real Firstbourne started attacking, Iron Baron saw what the Ninja had planned and ordered the Hunters to hunt for the Ninja.

The Gilded Path
The Ninja noted Wu grew older in his sleep. Wu mentioned his dream about fishing with Garmadon and the First Spinjitzu Master; Heavy Metal overhears this and reveals she's a woman named Faith. She asked if he knows where the Dragon Armor is. Wu pointed to a direction and they set off for the Armor.

When they are approached by Daddy No Legs and Muzzle, they Ninja tricked them and were able to tie them up. They stole their vehicles and continued driving toward the armor.

Two Lies, One Truth
The Dragon Hunters found Daddy No Legs and Muzzle tied up by Faith and the Ninja. They followed them, but were defeated when they reached the canyons. The Ninja failed to notice a tracking device Jet Jack attached to one of their vehicle.

The Ninja reached Oni territory and went in to look for the armor. They see the land was abandoned, but noticed the gates reveal a map to the Dragon Armor, which is located in Firstbourne's nest.

The Weakest Link
The Dragon Hunters stop looking the Ninja when they realized they crossed Oni territory. Iron Baron, however, ordered them to cross the land.

When the Ninja woke up, Faith handed them chain guns and they start training by chaining up a rock. When they, and Wu, succeeded, they have Wu ride Stormbringer.

When they stopped to look at their map, they realize the Hunters were following them. They were able to defeat them, but Faith has been captured.

Saving Faith
The Ninja uncovers Faith under the sand, but were surrounded by Dragon Hunters. They were tied up, but Wu escaped. He agreed to lead Iron Baron to the Firstbourne's nest while everyone else stayed behind.

Lessons for a Master
After successfully acquiring the Dragon Armor and subsequently the Firstbourne's trust, the Ninja and Dragon Master Wu bid farewell to Faith and the other Dragon Hunters before leaving the realm and beginning their journey back to Ninjago on the Dragons.

Inhabitants

 * Oni
 * Mistaké (formerly, deceased)
 * Dragons
 * Firstbourne
 * Ultra Dragon (deceased)
 * Slab
 * Stormbringer
 * Stormbringer's Baby
 * Wind Dragon
 * Dragon Hunters
 * Iron Baron (former leader)
 * Heavy Metal (leader, former second-in-command)
 * Jet Jack (current second-in-command)
 * Chew Toy
 * Daddy No Legs
 * Muzzle
 * Arkade
 * First Spinjitzu Master (formerly, deceased)
 * Creatures
 * Bonepickers

Visitors

 * Kai
 * Cole
 * Zane
 * Jay
 * Wu

Notable Locations

 * Oni Land
 * Dead's End
 * The Pit

Legend
"Long before time had a name, there was the Realm of the Oni and the Dragon; the Dragon had the power to create, the Oni had the power to destroy. Their war was never-ending. But a child arrived, born of both worlds. The child understood the power of both: without one you could not have the other. But when the Oni and the Dragon fought over which side the child should choose, the child abandoned their world to start a new one called "Ninjago." After the First Spinjitzu Master created Ninjago, he fathered two sons of his own. He thought he could escape the war. He saw the evil of the Oni was awakened to be unleashed in one of his sons—Lord Garmadon! It was up to Master Wu to control his brother's undying thirst to destroy, and with some help, Lord Garmadon was destroyed by the most powerful force of all—the love of his own son." —Mistake

Season 8: Sons of Garmadon

 * 77. "The Oni and the Dragon" (pictured)
 * 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"

Trivia

 * This realm is the homeland of the First Spinjitzu Master, a being born of both Oni and Dragon.
 * It is also home to the Firstbourne, the mother of all Dragons, and possessor of every Elemental Power that her children possess.
 * The Oni also live here, at least, they used to. According to a German magazine, they have mysteriously disappeared from the realm.
 * It also seems that the realm was divided into Oni land and Dragon land.