Phantasmagoria's Maw

Phantasmagoria's Maw is the doorway between the Ethereal Plane proper and Xibalba, a demiplane hidden in the Ethereal Plane and home of the sahkils. Outwardly, Phantasmagoria's Maw manifests on the Ethereal Plane as a vile mountain made of ectoplasm, sharp spires, and roots drifting into numerous planets in the Universe. Its interior is even more horrific: due to their mastery of teleportation, sahkils do not need conventional architecture; the most accessible parts of Phantasmagoria's Maw are death traps, while important chambers are hidden by illusions or accessible only via teleportation. On the peak of Phantasmagoria's Maw is the portal to Xibalba, which pours its horror into the Ethereal Plane and attracts swarms of allips and phantoms.