One of the longest and notorious acts in Diablo 3 also has one of the coolest boss fights in the game. The first phase of the fight is pretty simple; just beat the crap out of him. But when the second phase hits, things get really epic and exciting. Belial turns into his true form--which is a gigantic demon--and it’s up to the nephalem to avoid his meteor strikes, sweeping attacks and double slams. Definitely one of my favorite boss fights of all time.