Random fact:

Quite some Spells and/or chanting of spells used in Bastard!! are from more or less well known bands such as Black Sabbath, Slayer, Venom, Guns'N Roses, Sodom, Megadeath, Def Leppard ..

just to name some.. full list can be found on volume 8 of the manga.. at least in the german version. if you want a full translation bother Alexander to contact me ;)