Aku'mai's Lair is located within Blackfathom Deeps, and is the home of the servant of the Old Gods - Aku'mai. The great hydra is venerated by the Twilight's Hammer and the naga as a herald to a new age of darkness, where the terrible deities are brought free of their underground prisons and brought out to destroy all life.
Aku'mai's Lair lies beyond the Moonshrine Sanctum's double doors, and is the last area of the dungeon.
In order to gain access to Aku'mai's Lair, you must light the four Fires of Aku'mai that are around the naga statue in the previous room. A few waves of protectors will need to be defeated, and access will be gained.