Cross Serpent (series)

Cross Serpent (クロスサーペント) is a series of video games developed by Multisoft, known back then as Gamesoft. It follows Dragoon Viper, a young tribesman who is the victim of the "Crossgene Epidemic," as he protects the world from another worldwide infection with the help of friends such as Kidd Baxton, a fellow mechanic and the inventor of the K.Y.O (Kidd's Yielding Object), and Dai Andou, an enigmatic assassin and the father of Kai Andou. It originally started as a beat 'em up, but it later becomes an action-adventure game, and lastly a fighting game. There was also a crossover with another Multisoft franchise, Bomb Strike.

Cross Serpent: Virus Blitz
Dragoon Viper, a tribesman transformed into a reptilian Crossgene mutant after the "Crossgene Epidemic," finds K.Y.O crashed into his village. It warns him about the plans of BIOMIND, a secret organization hellbent on selling Crossgenes to further create their Crossgene army. After hearing this, Dragoon and K.Y.O leave the village (with the tribe leader's consent) and stop BIOMIND from conquering the world. On the way he meets Dai Andou, the mysterious assassin who attacks him not long after Dragoon arrives in Kodo Island, Kidd Baxton, K.Y.O's creator who is saved by Dragoon after being ambushed by an army of Crossgene robots, and Li Fon, a martial artist who left his isolated village to see the world for himself. Together, they form the "Virus Blitz" in order to destroy the Virus Machines operating in China, U.S.A., Europe, and Russia.

Cross Serpent 2: Victory Burst
The Virus Blitz has disbanded but are reunited to take on two new groups of enemies, the Saint Shields and the Bloodrivers. The Saint Shields' goal is to steal the Crossgene cure from the world to stop a life-changing event that happened long ago from repeating itself. The Bloodrivers also have the same goal, but their virus machines contain Bloodgene Mutants that are mutant doppelgangers to the heroes. Jessica Ambers, a researcher from the Tyosuta Association, appears to be relevant to the game's events as well, and the heroes must protect her from falling into either of the antagonists' hands.

Cross Serpent 3: Tag Attack
In order to face each other at the upcoming World Championship, Dragoon, Kidd, Li and Dai have once again disbanded the team and rejoined their home groups. With only Dragoon and Jessica left in the Virus Blitz, a new fighter, Astro Shotput and Dragoon's older brother Wyvol join them. Soon after the World Championship, the evil Cyrus forms CRYO as a replacement to the Tyosuta Association and to take control of all Crossgene activity. In order to stop Cyrus, Dragoon challenges him, which leads to the creation of the Universal 11 tournament with the fate of the world in the balance.

CrossXBomb: Exploding Fight
A non-canon crossover which takes place during Cross Serpent 3 and after Bomb Strike 2 (for the Nintendo DS).