This article is about a/an villain in Kamen Rider Build and Kamen Rider Ex-Aid. |
- "Kaiser!"
- ―Transformation phrase as Kaiser Reverse.[src]
- "Bikaiser!"
- ―Transformation phrase as Bikaiser.[src]
Kaisei Mogami (最上魁星 Mogami Kaisei) was the counterpart of Kaisei Mogami in the World of Ex-Aid. Using the Nebulasteam Gun, Kaiser become Kaiser Reverse (カイザーリバース Kaizā Ribāsu), also referred as Right Kaiser (ライトカイザー Raito Kaizā)
Character History
As Kaiser Reverse, this Kaisei Mogami made his appearance before the Gamer Riders at Seito University Hospital. Taking claim for the Nebula Bugsters unleashed there. Following his counterpart in the World of Build, Mogami activated the World of Ex-Aid's Enigma device, causing the Gamer Riders' transformations to be cancelled and rendering them defenseless. Kaiser Reverse attempted to kill the doctors only to be met by Kamen Rider Ghost, who assumed Newton Damashii to defeat the Nebula Bugsters accompanying him. Seeing his advantage lost, Kaiser Reverse took his leave. Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders
Post-mortem
Sento was reminded of the unification of the two Kaisei Mogamis into Bikaiser when he witnessed Fu Washio transform into Hell Bros. The Counterattack Hero
Personality
This counterpart of Kaisei Mogami is louder and more ruthless, and is more focused on the annihilation of the Kamen Riders than the humans.
Forms

Nebula Hell Bro's
Nebula Hell Bro's (ネビュラヘルブロス Nebyura Heru Burosu) is the basic body of the Kaiser with no Gears attached. Though typically bypassed altogether in the transformation to Kaiser, it is briefly seen during the transformation to the combined Bikaiser. Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders

Kaiser Reverse
- "Gear Engine! Funky! (Rock music, engine revving) Engine Running Gear!"
- ―Transformation announcement[src]
Statistics
Ability Perimeters:
- Punching Power: 20.3 t.[1]
- Kicking Power: 24.8 t.[1]
- Maximum Jump Height: 32.4 m.[1]
- Maximum Running Speed: 100 m. per 2.8 sec.[1]
Kaiser Reverse (カイザーリバース Kaizā Ribāsu) is the red Kaiser, also named Right Kaiser (ライトカイザー Raito Kaizā), accessed by inserting the red Gear Engine into the Nebulasteam Gun.
Kaiser Reverse's finisher is the Funky Drive (ファンキードライブ Fankī Doraibu): Kaiser Reverse channels the power of a Gear and performs a powerful blast attack.
- Gear Engine: Kaiser Reverse fires a large energy shot at the enemy, then follows it up with a roundhouse kick that leaves behind a trail of red energy.
Appearances: Heisei Generations FINAL: Build & Ex-Aid with Legend Riders

Bikaiser
- "Gear Engine! Gear Remocon! Funky Match! Fever! (Rhythmic beeping, engine revving) Perfect!"
- ―Transformation announcement[src]
Statistics
Ability Perimeters:
- Punching Power: 40.6 t.[1]
- Kicking Power: 49.6 t.[1]
- Maximum Jump Height: 64.8 m.[1]
- Maximum Running Speed: 100 m. per 1.4 sec.[1]
Bikaiser (バイカイザー Baikaizā) is the fusion of Kaiser and Kaiser Reverse, accessed when both Kaisers transform together.
Appearances: Heisei Generations FINAL: Build & Ex-Aid with Legend Riders
Equipment
Devices
- Nebula Steam Gun - Transformation device and sidearm.
- Red Gear Engine - Transformation trinket
Behind the Scenes
Portrayal
The World of Ex-Aid's Kaisei Mogami is played by Kenji Ohtsuki (大槻 ケンヂ Ōtsuki Kenji).
Conception
In the script of Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders, Kaisei Mogami's form was dubbed the R Kaiser (アールカイザー Āru Kaizā, Right Kaiser), equal to the L Kaiser.[2]
Notes
- Mogami is similar to Lem Kannagi from Kamen Rider × Kamen Rider Fourze & OOO: Movie War Mega Max. Both are members of Foundation X and main antagonists of their respective Movie War films.
- Notably, like Lem, he appears to be researching Core Medals and Astroswitches.
Appearances
Kamen Rider Build
Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders
- Episode 23: The Phantom of the West (archive footage only as Kaiser Reverse)