The Pandemonium in Askellon

[The Pandemonium in Askellon]

So does the Pandemonium have an actual physical location within the Askellon sector? Or does it just encompass the entire region?

[Anything in the rules about a Human champion of chaos?]

I'm writing a campaign about which features a Champion of Chaos as the BBEG and I'm trying to find a sourcebook that can quantify (or at least give me an idea) how strong they are or should be. It's possible I'm using the wrong term for a human that serves and has been chosen by a chaos god, but that's basically what I'm looking for.