|Home world:||Yapool's dimension|
|First appearance:||Ultraman Ace Episode 44: "Setsubun Ghost Story! The Shining Bean" (1973)|
Subtitle: Demon Super-beast (鬼超獣 Oni Chōjū?)
- Height: 57 m
- Weight: 31,000 t
- Origin: Space
An oni monster (possibly a Choju mutated from Yapool's remains) appears one day from a grey cloud. TAC arrived at the scene to combat the monster, but had trouble when members Konno and Hokuto's arms went numb, due to eating red beans. Hokuto transformed into Ultraman Ace, but Ace too was numb, allowing Onidevil to escape. With the help of Ultraseven Hokuto was cured. Onidevil reappeared this time forcing a daytime into a night with his Dark Zone. Ace showed up and was able to defeat Onidevil with little difficulty, curing everyone with numb arms.
- Onidevil uses an altered Baragon roar.
- Whether or not Onidevil was connected to the unlucky red beans is unknown.
Powers and Weapons
- Blinding Flashes: Onidevil is capable of emitting blinding flashes from his horn.
- Dark Zone: Using his horn, Onidevil can create clouds turning the area around him black.
- If the Onidevil's horn is broken off, he becomes completely powerless.
|Ultraman Ace Kaiju & Seijin|
|Verokron | Yapool | Chameleking | Vakishim | Garan | Aribunta | Giron Man | Brocken | Alien Metron.Jr | Doragory | Muruchi II | Gammas | Zaigon | Alien Antira | Unitang | Sabotendar | Barabba | Ace Killer | King Crab | Cattle God | Cowra | She-Devil | Hotarunga | Black Pigeon | Android Couple | King Kappa | Zemistlar | Aprasar | Aprasar Fairy | Space Mask | Black Satan | Giant Yapool | Mazaron Man | Yojo | Mazarius | Alien Orion | Sphinx | Alien Hipporito | Lunaticks | Undergroundmon | Gitagitanga | Red Jack | Baktari | Coakes | Bad Baalon | Kaiteigagan | Dreamgillas | Soundgillar | Machless | Snowgiran | Namahage | Alien Fire | Firemons | Alien Steal | Kaimanda | Shishigoran | Iceron | Woo II | Fubigirara | Onidevil | Gasegon | Daidarahoshi | Hanzagiran | Verokron II | Yapool Woman | Univerlages | Aquarius | Alien Revole | Signalion | Geegon | Alien Simon | Jumbo King|