Venosnaker resembles a giant mechanical cobra. It is able to spit out a thick venom from its mouth at the opponent that melts anything it touches.
Venosnaker was already contracted to Asakura's Card Deck before he became Kamen Rider Ouja. He played a pivotal role in the deaths of both Jun & Tezuka. Because Venosnaker is as tall as Dragreder, they have both fought against each other before on multiple occassions.
After a certain period of time, Venosnaker, who had not been fed by Asakura in a while, started to act violently towards him in breach of contract. However, Asakura was safely able to feed Venosnaker before it completely killed him.
Near the end of the Rider War, Venosnaker assisted in killing Goro Yura, who had taken up the Zolda deck from Shuichi Kitaoka.
It is unknown what happened to Venosnaker after Asakura died, but it is implied in the end that because the Rider War never happened, Venosnaker and all other Mirror Monsters did not exist anymore.
Kamen Rider Ryuki: Episode Final
Venosnaker first appeared in the film when Asakura summons it to fire its signature acid spit to melt Femme's Wing Shield. Later, again when Asakura used his Unite Vent card to combine his monsters into Genocider. Genocider was later destroyed by Kamen Rider Ryuga's Final Vent.
- Sword Vent: The tip of Venosnaker's tail is summoned and used as a sword by Ouja.
- Veno Crash (Final Vent): Venosnaker launches Ouja into the air, after which the latter performs a bicycle kick to the opponent.