Activate Krenko by tapping it, creating that many 1/1 Goblin tokens equal to the number of Goblins you control.
Cast Breath of Fury by paying ({2} magic symbol) ({R} magic symbol) ({R} magic symbol) , enchanting a Goblin token.
Move to combat.
Attack with enchanted Goblin token, dealing damage to player.
Breath of Fury triggers, sacrificing the enchanted Goblin and enchanting other Goblin token, untapping your creatures and gaining an additional combat phase after this one.
Activate Krenko by tapping it, creating that many Goblin tokens equal to the number of Goblins you control.