Board Thread:Warhammer 40k General Discussion/@comment-46.103.139.237-20130210211245/@comment-6078851-20130211034826

i assume there's an entry on this wiki somewhere, check that out for full details or read on for the gist.

the area of space known as the eye of terror used to be eldar territory but back in the day (i'm fuzzy on the date but thousands of years ago) the eldar fractured into the eldar and the dark eldar after the depradations of the dark part of eldar civilisation caused the birth of the chaos god slaanesh. the birth of slaanesh was accompanied by galaxy wide warp storms, the largest and most enduring of which was the eye of terror. the eldar homeworlds were located right in the centre of the cataclysm!

as for the fate of these worlds i don't know if they were destroyed or became daemon worlds, probably some of both, although i've never heard of chaos eldar.