There are two sets of Novels in Trinity Blood, Reborn on the Mars (R.O.M.) and Rage Against The Moons (R.A.M.). The events in Rage Against the Moons take place before those in Reborn on The Mars. The books were written by Yoshida Sunao (and after his death, continued by Kentaro Yasui) with illustrations done by THORES Shibamoto. There are also 5 manga volumes currently available; the anime is produced by GONZO and there are 24 episodes in total. Similar in feel to a Hellsing or Trigun. The background is in the distant future, a post-apocalyptic world after the destruction brought about by Armageddon. The war between humans (Terran) and vampires (Methuselah) continues, as a struggle between two factions: the Vatican and the New Human Empire. Yet amidst the bloodshed and violence, many desire a peaceful co-existence between the two species. However, standing between them and this goal is the Rosenkreuz Orden, a group of vampire extremists who manipulate the two sides and pit them against each other. To combat them, the Vatican special operations group "AX", led by Cardinal Caterina, must use everything they have - even a Crusnik (a vampire who preys on the blood of other vampires) to protect the peace effort.

(Source: Tokyopop)