As described in the book it is a rift in space leading to another dimension that was discovered by the founder of the Necromongers and only the Lord Marshal is allowed to enter, or even look at it, with a gate-keeper of sorts standing guard to ensure that no one but the Necromongers comes near. I highly recommend reading the book for a better definition. It seems to have been written on either the first draft of the film, or a fairly early one. Oh, and anyone that has said that Chronicles of Riddick starts slow needs to go back and watch Dune again! That's slooooooow!
Hells yeah kiddies...I might just actually go get this here book! I've been thinkin' about it, but I never really got around to it. Damn me and my procrastinatin' ways!!! Arggggh!!! Oh well...I'm out.
