It's more likely that the Dead End monster/King is the MC from the future than Deus. He did tell Valravn, during the flashback, that he reminded him of his Bride. I also recall Ella telling the current MC about Valravn being out there and to be careful. Ella equals the Bride and him recalling about her makes him remember about Valravn(future) so he turns the injured Raven into Valravn, unknowingly.
How would that make sense if that happened in the past but he's the MC? The MC got so powerful and batshit crazy in the future, he devoured and consumed everyone. When he regained his sanity, in the future, he flew himself into the past but went too far and shattered himself into pieces we know as the Numbered. Now he roams around for thousands of years waiting for the Numbered to leave their planes to regain his power back. Also, during the Dead End, you notice how Ella wasn't shown to be killed like Mother and the MC. It cuts as the MC leaves her.
If it wasn't obvious enough, I'm not being serious about the above lol.