The Beetle Fangire is the previous King of the Fangire race in the World of Kiva and the main antagonist of the "Kiva" arc of Kamen Rider Decade.
Kamen Rider Decade
World of Kiva
The Beetle Fangire was the King of the Fangire race until he was exiled for conceiving child with a human woman. His half-breed successor would grow up to be Wataru. Believing that coexistence between Fangires and humanity was nothing more than a farce, the Beetle Fangire breaks the peace between the two races by attacking humans to gather their Life Energy and reclaim his title as King. He also steals Kivat from Wataru, proclaiming himself as King of the Fangires.
However, the Beetle Fangire restarting past conflicts between humans and Fangires finally motivates Wataru to step up and claim his place as King of the Fangires. In his battle against the Riders, the Beetle Fangire was weakened by Decade's Kiva Arrow before receiving a fatal blow from a Dimension Kick/Darkness Moon Break combo.
Before he dies, the Beetle Fangire reveals to Wataru that he only to motivate his son to become the King he knows Wataru can be. As the previous King's body shatters, Tsukasa plays a final violin song for him.
World of the Rider War
Super Hero Taisen Z
The Beetle Fangire was one of the monsters in the Space Shocker army that battled a combined force of Kamen Riders, Super Sentai teams and Space Sheriffs as they approached the Genmu Castle. He fought Space Sheriff Shaider and was destroyed by Shaider's Blue Flash finisher.