You shouldnt.
Its an exact copy of the ice golemancer found on the ggg site.
Only thing i can think off is getting more damage by:
- leveling youre gems to the max or buy +21 / Awakened versions.
- have maximum sockets and jewels on passivs. You missing 1 or 2 if i am right. And 1 jewel is 60% damage
Because what you kill fast cant one shot you

My opinion is you need to get more experience in youre dodging skill

And one shoting is part of this game. Happens once in a while even with high experienced gamers.