DESCRIPTION:
I Haven't seen this uploaded anywhere on Youtube yet, so I thought I'd post it. This was recorded straight from the game itself, and carefully edited. It has everything from the boss intro and phase transitions to the music that plays when the boss is defeated.

I don't know what the actual name of the track is, but you're pretty much fighting *Spoilers*

Diablo, who has the Seven Evils inside of him that were absorbed into the Soulstone, thus, becoming The Prime Evil.