Vice is a demon born from Ikki's desire to protect others and Ikki's partner.
As a demon, Vice usually comes off as immature and mischeievous in contrast to his partner's mature and selfless personality.
Initially willing to go as far as devouring the souls of humans, Ikki's supervision of Vice keeps him grounded.
As Ikki and Vice's bond grow throughout the series, Vice dedicates himself to preserve his relationship with Ikki.
Forms a contract with Ikki at the start of the series to transform into Kamen Rider Vice.
Based on a Tyrannosaurus Rex. Rex Genome is the default form of Kamen Rider Vice accessed by Kamen Rider Revi, who inserts the Rex Vistamp into the Revice Driver.
Vice can shoot flames from his mouth via Revi's use of the Revice Driver.
Can combine with Kamen Rider Revi (Rex Genome) to form Revice Rex via the Revice Driver's Remix function.
Based on an eagle and Kamen Rider W. Eagle Genome is accessed by Kamen Rider Revi, who inserts the Eagle Vistamp into the Revice Driver.
Can combine with Kamen Rider Revi (Eagle Genome) to form Revice Eagle via the Revice Driver's Remix function.
Based on a pterodactyl, a hoverbike, and Kamen Rider Faiz. Ptera Genome is accessed by Kamen Rider Revi, who inserts the Ptera Vistamp into the Revice Driver.
Can combine with Kamen Rider Revi (Ptera Genome) to form Revice Ptera via the Revice Driver's Remix function.
Based on a jackal, a skateboard, and Kamen Rider Ex-Aid. Jackal Genome is accessed by Kamen Rider Revi, who inserts the Jackal Vistamp into the Revice Driver.
Can combine with Kamen Rider Revi (Jackal Genome) to form Revice Jackal via the Revice Driver's Remix function.
Based on a Brachiosaurus and Kamen Rider Zi-O. Brachio Genome is accessed by Kamen Rider Revi, who inserts the Brachio Vistamp into the Revice Driver.
Can combine with Kamen Rider Revi (Brachio Genome) to form Revice Brachio via the Revice Driver's Remix function.
Based on an egg, ice, and Tyrannosaurus Rex. Barid Rex Genome is Kamen Rider Vice's upgrade form that comes along with Kamen Rider Revi Volcano Rex Genome.
Uses ice-based attacks and retains the shield granted to him by Revi Barid Rex Genome.
Based on a Tyrannosaurus Rex and ink. Jack Revice is the super form for Kamen Rider Revice, accessed by inserting the Rolling Vistamp into the Revice Driver.
Jack Revice can be accessed either by Ikki or Vice.
Vice takes over Ikki's body after they transform into Jack Revice.
Has a power increase in combat and can move around to different positions after submerging into puddles of ink.
Uses the Rolling Vistamp as the default weapon.
Based on a Tyrannosaurus Rex and lightning. Kamen Rider Revice is Revi and Vice's combined super form and a step-up to Jack Revice.
Accessed by inserting the Thunder Gale Vistamp into the Revice Driver.
This form restores Ikki and Vice back to their normal places after dealing with the effects of transforming into Jack Revice.
Kamen Rider Revice uses lightning and wind-powered attacks and moves at high speed while in battle.
Combining Thunder Gale with another Vistamp allows Revice to execute strengthened attacks.
Additionally, they can separate Phase 3 Deadmans from their hosts.
Based on a Tyrannosaurus Rex.
Kamen Rider Vice's final form, accessed by inserting one-half of the Giffard Rex Vistamp into the Revice Driver.
Along with Ultimate Revi, the two Riders go by the moniker of Ultimate Revice. Ultimate Revice may be a subtle reference to the DoubleRiders from Kamen Rider (1971).
Can land strong hits on enemies and perform very high jumps, resulting in quick depletions of Giff Juniors.
Combining with Ultimate Revi's other half of the Giffard Rex Vistamp, Ultimate Revice can create duplicates of themselves.
Revice Driver's Remix function turns Ultimate Vice into a ball-like form that Ultimate Revi kicks to strike the enemy.
Finisher is called Vice Giffard Finish, where Ultimate Vice performs an intensive, spinning Rider Kick in the air with Ultimate Revi.