Warlock
2-Piece - Your periodic damage has a chance to summon a Fiery Imp to assist you in battle for 15 sec.
4-Piece - Your Shadow Bolt and Incinerate spells have a 5% chance to increase all Shadow and Fire damage you deal by 20% for 8 sec.
Copied from: http://wow.joystiq.com/2011/05/05/pa...ses/#continued
Note: These are from early PTR data mining. THEY CAN CHANGE!