definitly keep, I been reading that he has 600% modifier on third skill (first also nice not sure on %), so he could be nice KO monster when paired with another dps. Best runes should be Violent Blade with ATK/CrD/ATK this way if you put mob below 50% and you violent proc you can finish him. YDCB talked about 60K dmg in best case scenario. In future I will give a try to mine.
