Ogremoch

Ogremonch is a giant earth elemental worshipped by the Cult of the Black Earth. Also known as The Prince of Evil Earth or The Mountain That Walks
Domain Ogrémoch made his lair within the Plane of Earth, in a fortress known as Stonemire, on a plateau near the border with the Plane of Magma. The heat was unbearable and fountains of molten stone, smoke, and steam were used as decoration. Tales told of the foundations of the fortress being the entombed bodies of Ogrémoch's still-living enemies.
Personality Ogrémoch was wholly selfish, regarding all the wealth within the earth as his own. This was not because he needed the wealth, but because of the principle of the thing.[5] What he could not crush under his massive form, he outlasted.