Vampire Ninja (吸血忍者, kyūketsu-ninja?) is a class of vampires who are trained in ninjutsu. They are composed of many factions, who can oppose each other, and has unusual customs, including a kiss from the opposite sex as a sign of marriage. It is stated by Maelstrom that their names are not given to them until they've fulfilled their training or are deemed ready by the elders. They are the guardians of the Human realm.