This was pretty interesting. Kruul is a guy who appears at the entrance to one of the capital cities at random, and he's exactly the same as Kazzak, except that he has a bunch of (weak!) corehounds with him. (And don't get me started on why the Fire Elementals would never ally with the Burning Legion.) The problem though, is that it's right next to the UC entrance, and there are tons of people who've never done the Kazzak fight coming and going, and they like to stand around and spectate while Kruul is being fought, which means they're easily killed, which heals Kruul, which means they can't kill him in 3 minutes, which means he kills everyone within about 100 yards of him instantly.