Hm, I already wondered why the guy I had the idea from did 300k with Grasp when his skill says 15k.
For me until now the damage added up, the 7,5k in the vid was because of crit + Death Wish, but maybe it's only bugged at higher levels.
And yeah the phys armour is not the biggest deal as I initially thought, but the fact there are no phys resistances, only dodging which doesn't help vs skills.
