They're a new addition, only a few days old. Once you learn their weaknesses they aren't too bad. Fire arrows work alright, bronze bucklers can parry them fairly well, and axes shred them; a friend and I were able to kill one in about 5 seconds with two base level bronze axes, I imagine a fully upgraded bronze axe & buckler would make short work of them as would any iron gear. They're easy enough to farm before even fighting the elder without too much hassle.