Celtic Heroes

So today we are killing a 6 star level 160 boss in carrow, alls going well 15% hp left when the rage thing kicks in, it has already been hard enough to kill many rezs used, suddenly it starts to melee 7k damage kills everyone and resets. What type of unfairness is this we probably used about 30+ rez on adds and area spells prior to the rage spell and then it kicks in and ruins our hard work. This is not fair and this spell should be expelled from the game.