Mugen Shinshi

The first manga series introduces Mamiya Mugen, the child heir of a rich family that enjoys solving crimes for the Japanese police during the Showa era. Although young, he has telepathic powers and a keen intellect, and is helped by his faithful butler Alucard. Some of the cases he gets involved with are occult or supernatural in nature.

The series was revamped for the second manga publishing, Boken Katsugeki-hen, where the story remains almost the same, although containing more gags and humor. Mugen lacks any superpower now, and solves cases with the help of his butler Alucard and his love interest Atsuko. However, the shady story of his family intervenes as well, forcing him to confront his villainous father and aunt. This iteration of the series received an OVA whose story conflates and references several of the manga's chapters.

A much more serious, almost horror-oriented view of the series is given in its third continuity, Kaiki-hen, where Mugen is now a suave, distinguished ladies man in his twenties. He works mostly alone and meets a long string of lovers in his cases, but is helped by his spiritual powers and his mentor Professor Yokomizo. This style was kept in the work's fourth version, in which Mamiya has a different set of powers.

The last series is the trilogy Gensho-hen/Oma-hen/Meikyu-hen, in which Mugen is presented as a supernatural entity unrelated to humanity that fights monsters and demons.