The title revolves around Harman Smith and Kun Lan, who are demi-gods, fighting a battle of good versus evil over several centuries. In the game's present, Harman has taken the form of a sixty-year-old assassin who is bound to a wheelchair, tended to by a maid named Samantha. He is capable of manifesting seven personalities into the real world, each with their own personal style of killing; the group is collectively known as the Killer7. The dominant personality is Garcian Smith, who, while in the presence of security cameras or television sets, has the ability to call upon the six other members of the Killer7 at any time. The other six personas, all with the Smith surname, include aggressive Irish-American Dan, barefoot Japanese-American female KAEDE, albino British Kevin, Puerto Rican Coyote, young Chinese Con, and Mexican wrestler MASK de Smith. Unlike most multiple personalities in fiction (and all real forms of the disorder), Harman does not just think he is someone else; rather, his personas actually take on a unique physical body when called upon. During the course of the game, the player is introduced to other ghostly figures from Harman's past that attempt to help the Killer7, including Travis Bell, the first target Harman assassinated, and Iwazaru, a subservient personality that appears from time to time in order to give the player hints.
