His passive summons the golem first time, then if the golem is there he will do AoE damage with mystery, if the golem isnt there he will sommon it again.

Also his mystery cant be interrupted (can be acupunctured, immobilizerd or put to sleep though), maybe the reason why it isnt prompt.

Also he is like a tank and support at the same time, use him as part of the team supporting other strong ninja and not as main focus of team.