After witnessing his father being killed by the Creator God (Seikatsu), Sin-being one of the last Forthbringers-is tasked with stopping Seikatsu's reign. To do this, Sin must find Heavens Gate to become a Knight of Eve.

Sin ventures into a world of science, bloodlust and conquest. The endless conflict between humans and manifestors make for a challenging journey. Along the way, Sin develops his own ambitions learning to master his manifestation form.