I got a second sure of power on the level directly below the DH*. The artifact was devilbane, which IMO is pretty OP. I am cruising through the midgame with it and it is cutting through all enemies with one or two hits. I suppose its OP-ness is offset by its rarity, but still its a lot.

*First surge was on DH2 , I immediately exited the level before anything could move. I think the artifact is a melee weapon, guarded by a werewolf king and since I am playing an unarmed Monk I didn't bother for now. I will go back when I get on demand teleportation to see what it is. Given the fact that I am playing unarmed I expect it to be something epic.