O-Parts Hunter, known as 666 Satan (Japanese: 666 ～サタン～, Hepburn: Roku-Roku-Roku Satan) in Japan, is a Japanese manga series written and illustrated by Seishi Kishimoto. It was originally published by Enix, who later became Square Enix, in their Monthly Shōnen Gangan magazine from August 2001 to December 2007, with the chapters collected into 19...