Twelve-Winged Dark Seraphim
So... My guess for this whole situation is that it has something to do with Sacred... The Crystallizers have something to do with Sacred, and more to the point, I believe that the leader of Sacred was a Crystallizer. Here's my proof: The leader of Sacreds ghost or spirit was in the sanctuaries, and we know this because he bestowed Han Sen with something. The Sacred Alpha used to have the Extreme King as a subordinate so my guess for this particular scenario is that this was an area that was set up with the crystallizers tech to make the Extreme King stronger.