Oni land is a territory in the Realm of Oni and Dragons, where the Oni built strongholds and resided long ago. A divider made of dragon skulls piked on sticks separated it from the rest of the land. As long as the other inhabitants of the realm stayed on their side, the Oni would stay in theirs. It was deserted centuries ago for unknown reasons.
To steal the Dragonbone Blade from the Firstbourne, Iron Baron and several Dragon Hunters crossed Oni land, but only to discover that the Oni left the Realm of Oni and Dragons a long time ago. Iron Baron presumably killed his group and eventually stole the Dragon Blade from Firstbourne. But at the cost of him losing his arm and leg from the dragon.
- The dragon skulls on the sticks resemble the heads of the Ultra Dragon.