Buso Renkin was an anime series that ran from 2006 to 2007. In total 26 episodes of Buso Renkin were aired. Buso Renkin has no reported filler. Student Kazuki Muto is killed one night saving a mysterious girl from a monster, only to wake up in his school dorm, believing it to have been a dream. However, he soon finds out that dream wasn't a dream at all when a giant serpentine monster attacks him and his sister. Tokiko Tsumura, the girl he saved, explains that the monster is a homunculus. However she, feeling responsible for him, revived him by placing a Kakugane medallion in his chest, serving as a heart.