White swindlers (shirosagi) are those that cheat people to take their money, red swindlers (akasagi) are those that swindle the opposite sex, and black swindlers (kurosagi) are those that cheat the white and red swindlers. After his family is swindled by white swindlers, Kurosagi sets out to avenge them by becoming a black swindler.

(Source: Anime News Network)