Eltab

Eltab was a demon lord known as the "Lord of the Hidden Layer." Eltab appears as a fifteen-foot-tall humanoid with the head of a canine-like creature. His head sports numerous antlers and horns and his body was covered with bony dark red plates. He has slitted yellow glowing eyes.

Eltab ruled the 248th layer of the Abyss known as the Hidden Layer. It was a vast wasteland of boulders and fissures constantly beset with intense electrical storms, making it inimical to most life except for demons and deadly plant life such as viper trees, ironmaws, and bloodthorns. In the fifteen centuries or so of Eltab's absence, the Hidden Layer was fragmented into ever-changing fiefdoms as Eltab's former lieutenants, including the balor Ndulu, fought over the vacated realm.
Thanks to the bindings cast by the witches demon-binders on Eltab when they summoned him, they also somehow linked fragments of the Hidden Layer to Gendos, as well. Pieces of the layer, known as demoncysts, could be found scattered beneath the ground all over northeast Gendos.
The demon lord Eltab was a potent force in the Abyss, rivaling the powers of Graz'zt, Orcus, and even Demogorgon himself. However, during the ancient days of Gendos, the empires of Narfell and Raumathar engaged in a bitter war, which ultimately destroyed both empires. During this war, Eltab was summoned to Gendos by the so-called demon-binders of Narfell, so he could be used as a pawn against their hated enemy. Eltab led a demonic horde on the behalf of Narfell and invaded Raumathan, a city of Rashemen, which he quickly conquered and set up himself up as its ruler.
Eltab's rule was brief, as an alliance of spellcasters (including the Witches) overthrew Eltab. Eltab was forced to flee, but the witches caught up with him in the Krown Vale Wildlands, imprisoning him beneath the ground, and bound a dracolich called the Everlasting Wyrm to guard over him.