demo:
2 piece: Your Doom spell now summons Doom Guards instead of Imps. Doomguards deal 50% more damage.
4 piece: For the first 3 seconds after entering Demon form your Soulfire spell becomes instant cast and doesn't consume Demonic Fury or Molten Core stacks. This effect can only happen every 25 seconds.
2 piece: Agony has a 15% chance to proc 'Misery', causing your next two applications of Soul Swap to be free. This effect stacks 2 times. (15 seconds duration)
4 piece: Drain Soul generates a Soul Shard, 20 seconds ICD.
destru:
2 piece: Conflagrate causes your next Incinerate to be instant cast and not cost mana. Does not consume a Backdraft stack.
4 piece: Your Chaos Bolt spell deals 25% additional damage and Incinerate has a 10% chance make your next Chaos Bolt instant cast and not consume a Burning Ember. Effect lasts 10 seconds.