The series recieved an anime adaptation in 2003 by Gonzo, but it heavily derailed from its source material. In 2011, a series of OVAs produced by Madhouse called Hellsing Ultimate began to air. These OVAs are a lot more faithful to Hirano's manga than Gonzo's anime, but with some small liberties.
- Hellsing Organization: A British vampire-hunting organization founded by descendants of Abraham Van Hellsing, the man who originally defeated Dracula.
- Artificial Vampires: Vampires created thanks to the Millenium Organization's FREAK Program. They are not as powerful as True Vampires, but they are stronger than Ghouls.
- Ghouls: The result of a vampire biting an unchaste victim. They are weaker than normal vampires, and they are comparable to zombies.
- True Vampires: Former humans who decided to drink blood by their own will. They are the most powerful type of vampire. The only True Vampires known to man are Alucard and Seras.
- Iscariot Organization: The thirteenth section of the Vatican. They are bent on destroying unholy creatures and taking down the Hellsing Organization.
- Millenium Organization: A coalition of Nazis who want to start World War III by turning all of its soldiers into vampires.