Chattur'gha! Xel'lotath! Mantarok! - The Ancients of Eternal Darkness

[Yora]

I've seen a good deal of the game some time ago, and I really love the Ancient (except Ulyaoth, he's boring). And going in true Lovecraftian fashion, I want to incorporate them into my D&D campaign.

But is there actually much known about them? I barely remember much of the game, and it's unfortunately old enough to not have detailed descriptions of all its elements neatly written down somewhere online. At least that I don't know about.
Could anyone help me out with some background information on the four, or anything about their capabilities and behavior, if there is something known about it?

[BeerMug Paladin]

I'm not sure what information is available about these that isn't just vague hints and minor details. I mean, you get the impression that Pious is smarter than Chattur'gah when you get to see the conversations they have. And Ulyaoth is smarter than Pious. Xel'lotath is some kind of insane genius who needs help choosing a direction.

Chattur'gah is about brute power. Xel'lotath is about madness and chaos. And Ulyaoth is about misdirection and trickery.

And there's even less to really know about Mantarok. Only that it's supposedly more powerful than the other three as some kind of over-god being. But that might just might be because it's already been summoned into the world.

I'd say you're probably justified in making up whatever you like that fits in those general themes and it will work.