Bio Hunter Silva is a robot manufactured by the Anti-Bio Union to destroy anything with Bio Particles and a major antagonist in Choudenshi Bioman. He is the one responsible for the destruction of the planet Bio Star and seeks to continue his mission by destroying all Bio Particles in the universe.
Silva returns the main antagonist of the Super Hero Taisen movie where he is rebuilt as a member of Dai-Zangyack to hunt down the Kamen Riders under the title Rider Hunter Silva. However, Silva is eventually revealed to be real power behind Dai-Zangyack as he usurps control of the organization and forms an alliance with Dai-Shocker to eliminate both the Kamen Riders and Super Sentai.
During the war on the planet Bio Star, infused with half of the planet's supply of it, Silva was built and programmed to kill anything with Bio Particles. However, Silva follows his objective to the point of using his giant robot to destroy Bio Star before following a trail left by Bio Robo to Earth where he battles the Biomen when being targeted by the Super Sentai's enemies from the Neo Machine Empire Gear as they want to use Balzion.
In the end, Silva was destroyed when Balzion was defeated by a sudden charge of Bio Energy from Bio Robo.
Super Hero Taisen
Rebuilt by the events of Kamen Rider x Super Sentai: Super Hero Taisen as a member of the Dai-Zangyack, a alliance of Super Sentai villains led by Emperor Marvelous (Gokai Red), Silva is given a new objective in the destruction of the Kamen Riders.
However, Silva is eventually revealed to be the true mastermind behind the organization and becomes Dai-Zangyack's leader as his group and Dai-Shocker team up to wipe out both hero types to rule the world. With both the Super Sentai and the Kamen Riders seemingly destroyed, Silva and Doktor G of Dai-Shocker unveil their true plan to combine the Gigant Horse and Super Crisis Fortress together in order to create the Big Machine and use it to conquer the world.
But, Marvelous and Tsukasa Kadoya then reveal that they were aware of the Shocker-Zangyack Alliance and were only playing along to unearth the villain's scheme, and that all the Sentai Rangers and Kamen Riders who supposedly died were actually sent to a dimensional rift. As both the forces of the Kamen Rider-Super Sentai army and the Shocker-Zangyack Alliance assemble, Silva and Doktor G lead the Shocker-Zangyack Alliance into battle against the combined forces of the Kamen Riders and the Super Sentai. In the battle, Silva is destroyed by GokaiGalleon Buster's Tajador Charge when the Gokaigers take the form of Kamen Rider OOO's Combos through Gokai Changes.