General Vezax is the twelfth boss encounter in Ulduar. He can be found in the Descent into Madness guarding the Prison of Yogg-Saron. Mana-based classes will have to deal with a lock on their regen, but will be able to restore it by destroying crystals that drop a residue on the floor. The Hard mode requires players not to break any of these crystals and not regen any mana.