I just logged in after a long hiatus, and found my tribe surrounded by revenents. I counted 6 to the east, 3 to the north, 5 to the south, and 5 to the north. I was completely surrounded, so we just stared at each other for a bit and then I logged out.
How hard are they, for someone with noob level combat experience? They didn't seem agro to me from about 40 feet away, although I think one did try to chase me.