Oni

The Oni were a race of demons. They were the first evil to ever come into existence, as well as the creators of the three powerful Oni Masks. They inhabited the Realm of Oni and Dragons, the first realm in existence. It is unknown what the whereabouts of the majority of them are by the time of Season 9. They lived in Oni Land, a forbidden part of the Realm of Oni and Dragons.

History
Before the existence of any other realms, there was the Realm of the Oni and the Dragon. In this realm existed two races; the Oni and the Dragons. The Dragons had the power to create, while the Oni had the power to destroy, and so they waged a never ending war against each other. One day, however, a child was born, having both the powers of Destruction and Creation. When the Oni and the Dragons fought over which side the child should choose, the child left their world to start a new one, called "Ninjago."

Soon afterwards however, some of the Oni pursued the child to his new realm of existence, creating a temple deep within Primeval's Eye, where they depicted their origins on the walls of the temple. They would also seal away the Oni Mask of Hatred within the temple, which could only be taken by a being with Oni blood.

Thousands of years later, in the present, the majority of the Oni have disappeared and it is unknown what happened to them. A city of the Oni was found in disrepair, having been abandoned for centuries. The only full-blooded Oni that was known to be alive is Mistaké, who lived in Ninjago shapeshifted into human form.

Known Oni

 * Mistaké

Hybrids

 * First Spinjitzu Master (of Dragon descent)
 * Garmadon (of Dragon and human descent)
 * Lloyd (of Dragon and human descent)
 * Wu (of Dragon and human descent)

Trivia

 * The Oni are based on Japanese folklore.
 * The Oni were the first evil to exist in the realms. However, because of Mistaké, it's known that not all Oni are evil.
 * According to a European Ninjago magazine, the Oni have mysteriously disappeared from the Realm of Oni and Dragons.
 * In "Two Lies, One Truth," it is revealed that there is a specific area of the Realm of Oni and Dragons that the Oni lived in.
 * The Iron Baron and his Dragon Hunters have never seen an Oni, so they mistook the Ninja for Oni.
 * According to the Iron Baron, Oni are shapeshifters.
 * This was later confirmed in "Two Lies, One Truth," where Mistaké shows her powers.
 * It is unknown if in addition to her, there are more Oni in Ninjago.
 * Lord Garmadon’s corrupted form resembles an Oni.

Gallery
Oni