The Monkey King was never mentioned in the Manwha but I also don't consider the recent revelation to be out of place. Earlier in the series it was mentioned that Jin Tae-Jin found Mori abandoned in the mountains which happens to be the same location where the Monkey king was imprisoned
So, not the moon then?
After he took the sage pill and collapsed while fighting Judge Q his aura was shown and it resembled a monkey.
I see I have missed some clues. Although, it is a bit of leap of faith to take that clue and say that Jin Mori was anything but human. I mean, at that point in the story we were being introduced to "ability users" who could do supernatural things. And then later on we were told that Jin Mori was a "power user." I don't think there was anything there that would have suggested that Mori was some sort of a reborn god. A stronger than average fighter, yes. But anything mythological, no. Not so much.
From the recent chapters the head band he wears is showed to act as a seal preventing him from reverting to his other form,
From recent chapters or from this latest chapter? Because if you mean this latest chapter then that doesn't count, seeing as how it is the chapter in question.
this can be compared to the magical headband the Guanshiyin (who?) gave Xuanzang (what?) as a way to control him.
In "Journey to the West," or this story?
I have no major issues with the current chapter there were clues however little and Jin Tae-Jin did say that Mori would have been enough to kill them.
I know I don't sound like it, but I have no major issues with this new development either. I am just stating that it did come out of nowhere. I see that I have missed some clues, but nothing that I think could possibly suggest that Mori was some sort of demigod.