Originally Posted by
Feronar
The problem is pretty much the exact same as WoW had at the end of Mists of Pandaria. Blizzard had to design around the problem in Siege of Orgrimmar, the final raid. The second-to-last boss, Paragons of the Klaxxi, was actually multiple bosses daisy-chained together, and the final boss, Garrosh Hellscream, self-healed twice over the course of the fight (Three times if playing on the highest difficulty level). Garrosh's effective total HP across all phases was about 3.77 billion (37.7億) on 25 player heroic difficulty.