Based upon the adult horror novel "Wolf Guy," created in 1969 by writer Kazumasa Hirai (best known for co-creating the manga superhero '8-Man' with artist Jirô Kuwata). The novel was translated into a manga for "Bokura Magazine" in 1970, and illustrated by Hisashi Sakaguchi. The manga was remade in 2007 by writer Yoshiaki Tabata and artist Ayumi Izumiya. The remake is more well known in American manga circles.
The wolf mask worn by actor Tarô Shigaki (when he becomes the werewolf hybrid version of Wolf Guy) was made with real Siberian wolf fur. Each strand of fur was interwoven into the mask.
For the scenes where Akira Inugami is fully transformed into a real wolf, a hand-puppet (with light-up eyes) is used in close shots, while a German Shepherd is used for full action shots.