Zllyphan

The Zllyphan are an eldritch race of alien energy beings in the pencil-and-paper roleplaying game Rifts by Palladium.

Background
During the Dark Ages, Earth was visited by a Zllyphan known as Zazshan who arrived after the fall of the Roman Empire. He planned to conquer the Earth and established himself on the British Isles. Where it used one of its meat puppets (Myrrlyn, aka "Merlin") to manipulate the Celtic-Roman tribes into creating the kingdom of Camelot.

Unfortunately for Zllyphan, the Atlantean cataclysm which occurred 1000s of years earlier was still playing havok with Earth's magic. Which resulted in Zazshan losing control of Camelot and its imprisonment in a crystal chamber deep within the Earth. Where it would lay trapped until the cataclysmic eruption of the ley lines a 1000 years later awakened him.

He reestablished his kingdom of Camelot and this time is using three meat puppets a benevolent sorcerer (Myrrlyn), King Arr'thuu's beautiful queen (Lady Guinevere), and the goddess (the Lady of the Lake), to manipulate King Arr'thuu. Whom Zazshan chose to act as the unknowning figurehead of the realm. Zazshan is a patient entity, as he first "unites" the British Isles under Camelot, after which he plans to do the same to Europe and then the rest of the world.

Zllyphan
Zllyphan are a malevolent race of manipulators, alien intelligences whom are beings of energy that appear as giant energy spheres the size of a house. Electric-like energy crackles on the sphere and around the body. Zllyphans on average live 120,000 years. Beings with formidable magical and psionic abilities. Which fire destructive energy blasts and are capable of surviving a 6.5 megaton nuke, though with grievous wounds. They can splinter their essence into smaller shards, and send those shards into other dimensions. All of which are directed and controlled by the core.

They can possess those whom have recently died and resurrect them. The corpse which is controlled by the shard does not look, act, or smell like one of the undead. It breathes, talks, walks, eats, drinks, and so on just like any other living being. Magical items, psionics, magical creatures, and supernatural beings inflict far greater damage on a Zllyphan compared to a laser beam, a plasma cannon, explosives, poison gas, acid, steel swords, or any other type of conventional weapon.