This dark, empty, and completely flat Shadowrealm is a prison for the Mother of all Gods, Coatlicue, which she both escaped and then was again entrapped in, in The Necromancer. It is a horrible place with no light and no end, used to keep Coatlicue away from the other Worlds and Elders after she went insane. She escaped the realm when John Dee used the Four Swords of Power to create a Leygate into the Shadowrealm. Coatlicue was lured out with the promise of Josh Newman's powerful and rare Gold Aura, and she nearly got her reward, but Aoife, Niten, and Sophie Newman stopped her, by attacking her relentlessly, wrestling her away from her prize. Aoife eventually managed to force Coatlicue back into her Shadowrealm, but she was forced in as well, and remained there, trapped with Coatlicue in eternal battle and endless darkness. At the end of The Enchantress, it is assumed that Niten went back into Coatlicue's Shadowrealm to rescue Aoife, and succeeded. It is also presumed that Coatlicue remains there, trapped until there is another window of opportunity to escape.