Who wrote the Undertakers theme song?

I'm not 100% sure who sings Undertaker's "Big Evil" theme, but I do know that Undertaker's "Big Evil" theme is partially sung by none other than Kid Rock. However, I don't know who is singing with Kid Rock in Undertaker's "Big Evil" theme.

Kid Rock sings Undertaker's American Bad A** theme. His Big Evil theme is performed by a band called Brand New Sin.