Trinity Blood (トリニティ・ブラッド, Toriniti Buraddo?) is a series of Japanese light novels written by Sunao Yoshida with illustrations by Thores Shibamoto and originally serialized in The Sneaker, freely inspired by a historical personality, Caterina Sforza. Set 900 years after an apocalyptic war between humans and vampires, the series focuses on the on-going cold war between the Vatican, the human government, and the Empire, the government of the Methuselah. Fighting on the Vatican's side is Abel Nightroad, a Crusnik–a vampire that feeds on vampires. A blend of sci-fi, fantasy, and political intrigue, as some in the Vatican and the Empire strive for peace, the Rosen Kreuz Order will do anything to stop it.
Trinity Blood has been adapted into both manga and anime series, with continuity differences between the three versions. After Yoshida's death on July 15, 2004, Kentaro Yasui, his friend and the author of Ragnarok novels, stepped in to complete the remaining novels. Yasui also aided in completing the manga, with illustrations by Kiyo Kujō. The anime series, spanning 24 episodes, was produced by Gonzo and originally aired on WOWOW network