The Dweller Beneath

The Dweller Beneath is a ridiculously insane Lovecraftian-like entity in the Palladium Rifts Megaverse roleplaying universe. It is a malevolent and sadistic entity with the craziest agenda of all the villains in the Rifts Megaverse.

Biology
The Dweller Beneath has lived for a million years and has a bizarre Eldritch Lovecraftian form. It's body is in the shape of a pillar, consisting of a moldy flesh. On top of the pillar is a giant cyclopean and a kind of hair grows out of the upper part, greenish in color. Sustenance is via feeding on the psychic suffering of sentients.

Powers
It has vast psionic and magical powers. The Dweller Beneath is able to communicate telepathically at galactic distances. It's capable of shapeshifting and it can increase its size up to 2 stories in height. The being can send out fragments of its lifeforce which can take any form and remain in telepathic communication with the core. An ability that it has is bestowing a tiny fraction of its power on a minion. It has the ability to regenerate and is able to survive a direct hit from a nuke with a yield less than 20 megatons (though it would be seriously wounded). Each of its fragments is extremely durable, 7-8 times as tough as a late 20th century Terran main battle tank. Runic weapons and those weapons made from the mystical Millennium Tree are able to inflict far more damaged to it than explosives, projectile guns, or energy cannons.

Agenda
The Dweller Beneath has an outrageous plan, which is to consume all life in the Megaverse, both psychically and physically. It's a plan that it figures will take it another million years to bring it to fruition. As part of its plan, it freed one of the Splugorth's minion races from their control, the Kreeghor.

They have served it's secret agenda perfectly as being a warrior race they have built themselves a totalitarian integalactic empire across the so-called "Three Galaxies". Only the Kreeghor Emperor knows the truth and his successor is always summoned by the Dweller Beneath before assuming power, where it learns the truth and is bestowed with a tiny fraction of its power. It uses the "Trans-Galactic Empire" as a tool against opposition and as a banquet, feeding on the psychic suffering of its trillions.