Well, Black Metal isn't just about Satanism, there are other topics, such as vampirism, lycanthropy, sodomy, forests, all of the afforementioned together ( ie a werewolf sodomizing a vampire in a forest. I think thats what Amor E Morte by CoF is about now that I think about it) paganism, heathenism, Viking God worship (see Viking Metal) wiccanism, goats, being kvlt (kvlt being 'cult' in norwegian) sodomizing goats, bleeding goats, sodomizing goats, death, and various goth-ish topics also pervade the wonderful sub genre that we call Black Metal.