Sirius Tenrōin is a fallen fairy from the anime *Fairy Ranmaru*, appearing as a secondary character. He possesses a slim build, dark skin, white hair, and blue eyes. His attire typically includes a beige gown worn over a white shirt, white flared trousers, formal shoes, and a black necklace with a small golden trinket.

Driven by intense hatred for the Fairy Queen, Sirius Tenrōin's primary objective is to destroy both the fairy and human worlds and kill her. This vendetta stems directly from his status as a fallen fairy. A significant, initially ambiguous connection exists between Sirius and Ranmaru Ai's past. Sirius's betrayal of the fairy kingdom led to catastrophic consequences: distraught over Sirius's actions, Ranmaru destroyed the kingdom, attempted suicide, suffered amnesia, and permanently damaged his left wing.

Sirius remains unaware of Ranmaru's romantic feelings until Ranmaru confesses in the series finale. His role culminates in the revelation of his past ties to Ranmaru and his broader mission of vengeance against the Fairy Queen, positioning him as a catalyst for key events in the story.