Did not realize this till I pulled up the video to show someone what I meant by Holy Diver. The Druids are a reference to the song.
http://www.youtube.com/watch?v=Sj7UBgVVew8
Also for the Rapers
http://www.youtube.com/watch?v=lidJPARmp68
Rocky area outside the gate area with the anvil head that leads to Lionhead. The area seems to be reference to the Angel Witch cover
http://www.youtube.com/watch?v=HXZc9-mtFDk
I may be wrong here, but I think this is the reference for the Ice Area is this cover.
http://www.youtube.com/watch?v=klweUM8wj4g
Something that may be reference to someone in Deviculious' army
http://www.youtube.com/watch?v=LbCKgLIHERo