BASTARD!! -Heavy Metal, Dark Fantasy-

Modern civilization and the world was destroyed by the God of Destruction, Anthrasax, in 7 days, and then is sealed. Hundreds of years later, the sorcerer Dark Schneider leads a group in an attempt to control the world. Dark Schneider, in the end, is sealed in the body of a young baby, Rushe Ren Ren. 15 years later, his group, minus Scheider, attempts the same mission by unsealing Anthrasax so they can redo the world. To save the Kingdom of Metallicana, a girl named Yoko releases Dark Schneider from her friend Rushe. Now, Dark Schneider fights his former comrades, but not for good; he fights to protect Yoko, and to have some destructive fun. <em class=de-emphasized>(from manga)</em>

Synopsis from Anime News Network