Thank you very much for the reply. Now that you mention it, just leaving the debuff is a pretty silly idea. As to why we used TW on 2nd dark phase, cause I figured if we did then he'd be dead in or shortly after the 3rd dark phase. Just shows my lack of experience there. I am happy that you did provide so much information and will be modifying our strategies for this week. However, I wonder why it is that you say he takes more damage during the dark phases. I do not remember seeing an extra debuff on him during the phase. Does he just take damage from the black blood also or something like that?
Also, I did not realize he was about to berzerk on our one good attempt. I thought we may be getting close to it,but did not know for sure. Yes, I know there's add-ons for that, but I don't use any. Call me what you will.

