Itzyoyotl, the Obsidian Heart

The mysterious prisoner of the sarcophagus found in the ruins of the The Copper Tower.

Little is known for certain, but apparently she was an Overseer in the time before the Shattering, before she was cast down by her fellow Overseers for pursuing forbidden knowledge. Whatever this knowledge was, she later claimed that the other overseers stole her work and brought it to it's conclusion.

In the current time, she is trapped in the dreamlands, forced to live in a nightmare version of her own castle from before, served by faceless minions.

For the last year or two, she has actively been trying to escape her prison by using her power over dreams to influence the weak minded.

In her current form in the dream lands, Itzyoyotl looks like a 3m tall skeletal woman dressed in a strange white suit of bandages and leather straps, over which she wears a voluminous dress of white silk splattered with blood stains. A veil covers her face at all times, but her skin as visible on her hands is greyish white with long black, iron-like, talons.

She seems quite deranged.