2010-04-03, 09:14 PM
Time it. He only casts it once every minute and it lasts 10 seconds, meaning you have 50 seconds to attack. Once he's getting toward 50% HP he starts using it, so start being careful. Then, one he's used it, as soon as it disappears go nuts until you believe around 40 seconds are up (I usually went for 30 seconds to be safe). It takes a while but you'll do it without dying for sure.