I love satanic black metal is that a sin?

No. It shouldn't be a sin necessarily. If you don't subscribe to the same ideals expressed in that music like murders or rapes or drugs and violence in general then you should be ok. It's simply an art form. However, if you find it corrupting you or those around you and has more of an effect on you than you want it to, then you should probably stop listening to it. Sins are usually actions that we take. Unless the music promotes you to think or act out a certain way, it should be fine.