Time for a "create a new faction in WH40K" thread. But with a twist. The new race can be birthed out of the destruction of other races/factions.

Here is mine: Reborn Eldar who came to power after the emperors death.The death of the emprah resulted in a massive shift in the warp and very suddenly brought the chaos gods to there knees. The eye of terror collapsed and from the destruction re-emerged the Eldar.

Picture somewhat related. I can't decide if they should be led by a new Chaos god, or perhaps the most fit of the old Eldar gods or maybe there just back and kicking everyone's ass somehow.