The Dominion is the most potent power in the galaxy, its past shrouded in mystery and legends. 
For three millennia the line of Hester has ruled over the growing empire unopposed and unbroken. All of that wouldn't have come to pass if not for the Godslayers and all the secrets they have kept hidden for generations.
It is their victory over the Hollow Gods which still echoes and shapes the Dominion so many centuries into the future. It is those same secrets that can burn it all down, for the Regis is about to wake once more and mark the start of a new cycle of violence. 
With their numbers diminished, it is unclear if they can remain to be the Slayers of Gods.