Nightwalker

A Nightwalker was a type of nightshade; a sentient undead monster from the Plane of Shadow. It was unnatural and malicious, and it took delight in the corruption and suffering of others. It was a creature of both death and shadows, and had enormous powers over darkness.

Description
A nightwalker's body looked as if it was made of shadow-stuff, with a vaguely humanoid form. They were about the size of a house, but were usually no taller than 20 ft. (6.1 m), and their bodies were smooth and hairless.

Abilities
Nightwalkers were surrounded by an aura of desecration, which could drain the life from living beings. They were also powerful spell casters, and had the ability to control armies of the undead. Their abilities became more powerful in the darkness, and they became weaker in sunlight, and some had spells that allowed them to block out the sun to protect themselves and other forms of undead. Nightwalkers also possessed the ability to communicate telepathically.

Other
Nightwalkers were more common in the ancient days of Imaskar. Nightwalkers were the shades of extremely strong-willed and evil mortals whose ancient and unyielding will and malice allowed them to hold there corporeal shape.