The interpretation is subjective.
This isn't drawn into the manhwa, but I'm getting the impression, what if God's visage was only a product of his mind caused by his desperate plea for atonement? Maybe, he found the relief he couldn't find anywhere else in degeneracy. Then he started to believe his lunacy as real.
Michael was riddle by his own demons (metaphorical) he saw the Priest like beacon and condemned himself for having forbidden feelings toward him. There are nuance that although he is religious, he lacks faith in their god because of the bad things happening around him.
Maybe he got roped into it because both of them weren't pure in the first place. And the label pure that's repeatedly mentioned in the chapters didn't entirely mean pure at all, but tainted. Yet, because he couldn't overcome the grief, he clung onto the word pure and deluded themselves.
At the end, both of them surrendered to the relief. Michael accepted the priest because he had feelings for him, but I get the impression this wasn't how he wanted it to be. And they looked sadder than before.
I am getting a impression that u r really good at writing answers on exam . Only if I was this good
what… so was the so-called ‘god’ a demon? and he used bence to create more and then the poor lad got roped in too?