i was stuck on this **** too
use snow, vanille, and lightning, buy silver bangles, and give it to lightning if you dont have at least 1500 HP...paradigms= snow=setinel lightning=ravager vanille=medic

when u take out the heads, just use snow and lightning as commando and vanille ravager, when they need health jus change vanille to medic... when he uses destrudo, use lighning a medic, snow a sentinal, and vanille a medic... and repeat make sure if u want to put some damage in to him whens hes charging destrudo hit him when all r ravager and he should get hurt and reset then use the thing i said earlier...hurry up though or he uses doom on lightning