Haku is actually really strong @ 3 stars. If you are lvl60+ azure fang,pair him up with Suigetsu,Zabuza -equip a summon capable of changing repulsed units into low float combo,equip water enhancement on azure fang and see the destruction you'll cause. Both azure fang and haku are capable of accupunctue and interruption. Zabuza can blind enemy units and Suigetsu can reduce opponent's attack.