Lycanthrope Leo (Japanese: 烈王, Hepburn: Reo) is a Japanese manga series written by Kengo Kaji [ja] and illustrated by Kenji Okamura [ja].

It was serialized in Shogakukan's seinen manga magazine Young Sunday from 1991 to 1993, with its chapters collected in four tankōbon volumes.

Written by Kengo Kaji [ja] and illustrated by Kenji Okamura [ja], Lycanthrope Leo was serialized in Shogakukan's seinen manga magazine Young Sunday from December 27, 1991, to September 10, 1993.

[a] Shogakukan collected its chapters in four tankōbon volumes, released from July 4, 1992,[7] to November 5, 1993.

[8] In North America, the manga was published in an American comic book format by Viz Communications, with seven issues released in 1994.