From Hellgatewiki.com

Evolution of a Nightmare feature by Ivan Sulic. Archived from the official site.

• Nightmares are covered in the monster section.
• See screenshots of Nightmares in the Image Gallery.

A Nightmare

"Kill me so that I can wake up from this un-living nightmare," is probably what these vicious skeletal bastards of the demonic Necros caste think every second of every day. Well, it's either that or, "Aaaiiiyyyeee!!! Sweet lord, my life sucked when I was alive and now I'm a purple being with poisonous green mist shooting out of my freakin' head!!! What the heck is up with that!?!"

Honestly, we just don't know what the Nightmare spends its days thinking about. But it can't be good given how wicked it is.

What we can be sure about, however, is the slow and steady evolution of the Nightmare from a bipedal collection of mist and shadow to a shrieking undead entity. See!

"These twisted fiends are the un-living remains of those unfortunates who were slain in their sleep. The bodies and faces of Nightmares are eternally contorted, reflecting the state of their minds and souls when the demons took control of them. Their anguish is what fuels their arcane attacks, making them frightening to see and a horror to battle."