Birugenia is a warrior serving Gorgom and a minor antagonist in Kamen Rider Black. He makes his first appearance in episode 18.
He was born 30,000 years ago on a day of a solar eclipse, just like Kotaro and Nobuhiko. However, a Kingstone was never given to him because the Creation King didn't favor him and therefore he could not become the next Creation King. This made him angrily trying to revolt against him and resulted with the Creation King sealing him in a coffin. The Creation King ordered the three High Priests to release Birugenia after they kept failing to retrieve the Kingstone from Kotaro. He was both a pain for Kamen Rider Black as well as to Gorgom.Birugenia always wanted to be the one to kill Kamen Rider Black, thus kept interfering in the High Priests' plans. In episode 22, Birugenia went back to his old white face form from 30,000 years ago, making him more powerful and more arrogant. In episode 25, he had Yoichi Daimon's pupil, Egami, create the Hellshooter: an equivalent to Road Sector. He used it to challenge Kamen Rider Black and Road Sector, only for the Hellshooter to be destroyed. During Gorgom's latest attempt to use Kyoko's lifeforce to awaken Shadow Moon, Bilgenia stole the Satan Saber and attacked the High Priests before running off with Kyoko and going after Black to take his King Stone for himself. However, Kotaro and Kyoko manage to hide from Bilgenia as he decides to attack the city to flush Kotaro out by using his Satan Cross to cause anarchy with a group of young men. Arriving to the scene, Black battles Bilgenia until Shadow Moon finally awakens and he claims the Satan Saber, forcing Bilgenia to retreat as his influence wears off. Returning to the Gorgom shrine, Bilgenia fought Shadow Moon who disarmed and then killed him.
Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai
Birugenia was revived as a member of Badan Empire.