Kaisei Mogami (World of Ex-Aid)

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 is one of the two main antagonists of Kamen Rider Heisei Generations Final: Build & Ex-Aid with Legend Riders alongside his doppelgänger. He was a scientist of Foundation X who transformed into , also referred as . 
==History==
===Background===
Kaisei Mogami was a scientist working under Foundation X who created duplicates of Core Medals and Zodiarts Switches. Through contact with his counterpart from Build's world, Mogami created his own Enigma built to solely transit between Build and Ex-Aid's worlds as well as his own version of the Kaiser system to transform into Kaiser Reverse.
===Kamen Rider Heisei Generations FINAL===
Mogami would finally complete Engima and unleash the Nebula Bugsters from his native world. Under the guise of "Right Kaiser", he intercepted the Doctor Riders and ensured their Gamer Driver technology wouldn't work as long as Enigma was activated. However, he didn't expect the intervention of Kamen Rider Ghost and is forced to evacuate.
Mogami would continue to work alongside with his counterpart from Build's world to use their Engimas to assimilate their worlds towards destruction. He would manufacture clones of Greeed and Zodiarts using his research from Foundation X to challenge the Kamen Riders from his native world. Eventually, both Mogamis would finally meet as the Engima was fully bridged both of their worlds, fusing into Bikaiser. However, Kamen Rider Build would join forces with the Kamen Riders from Ex-Aid's world to put a end to Bikaiser's megalomaniacal schemes and perishes from Build Rabbit Tank Sparkling and Ex-Aid Muteki Gamer's Rider Kicks.
==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==
== Foundation X Clones ==
Kaisei Mogami was able to utilize artificial recreations of most of the Core Medals as well as several Zodiarts Switches in order to create fake Greeeds and Horoscopes with the aforementioned recreations functioning as supporting henchmen who are assigned the task of being his enforcers as he is carrying out his nefarious scheme of fusing the two worlds together.
Artificial Greeed 
File:KRO-Ankh (Complete).png|Ankh (defected when the real Ankh's temporarily restored consciousness had entered the artificial clone's body)
File:KRO-Uva (Complete).png|Uva
File:KRO-Kazari (Complete).png|Kazari
File:KRO-Gamel (Complete).png|Gamel
File:KRO-Mezool (Complete).png|Mezool
Artificial Horoscopes 
File:KRFo-Scorpion Zodiarts.png|Scorpion Zodiarts
File:KRFo-Cancer Zodiarts.png|Cancer Zodiarts
File:KRFo-Leo Zodiarts (With Claws).png|Leo Zodiarts
File:KRFo-Virgo Zodiarts.png|Virgo Zodiarts
==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 . As Kaiser Reverse and Bikaiser, his suit actor is .
===Conception===
In the script of Kamen Rider Heisei Generations Final: Build & Ex-Aid with Legend Riders, Kaisei Mogami's form was dubbed the , equal to the L Kaiser.https://www.daily.co.jp/gossip/2017/12/09/0010803327.shtml
==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 
**Episode 27: The Counterattack Hero 
==References==
==Navigation==
Category:Movie-exclusive Villains
Category:Ex-Aid Characters
Category:Deceased
Category:Foundation X
Category:Debatable Riders
Category:Build Riders