When does Trinity Blood return?

Trinity Blood is a series of Japanese light novels written by Sunao Yoshida with illustrations by Thores Shibamoto. Set 900 years after an apocalyptic war between humans and vampires, the series focuses on the ongoing cold war between the Vatican, the human government, and the "New Human Empire" The novels blend science fiction, fantasy, and political intrigue, with some in the Vatican and the Empire striving for peace. The anime series, spanning 24 episodes, was produced by Gonzo and originally aired on Wowow network.