Not much info on him here, so hope someone will find this info when in need.
I curiously went to see Huntmaster after completing his event in Lesser Faydark where he took my bow and an hour later made a couple groups after my scouting to Loping Plains. As soon as he was in view, he said something, and within a few seconds I had 3 of his wolfs on me, they were not bad, they hit 200-400 each, but there was 3. I made a run for Lesser Fay, which was so close, however the Huntmaster was also on me... who hit for 2 to 3k. Now that I knew he was no easy task I called upon some help. I had a tank (guardian) for the Huntmaster and a paladin for the adds. We simply ignored the dogs and focused on the Huntmaster initially however the casters died. Second time around we killed the adds around us, then killed the dogs once they spawned on us, then we charged the Huntmaster (he is leashed!!!, while he may initially charge at you, he will randomly go back to his spawn point. My strategy to anyone is to kill the wolves once he summons them (he will stay at his spawn, the dogs will be on top of you). once the wolves are dead, tank charges Huntmaster and its about a 3 minute fight with a pickup group of level 70s. suggest 2 healers, 2 tanks, 2 dps. Of course, the more the merrier, and easier