honestly, i also just saw this on like the comment section here before, but it got burried down now. so i’ll just copy paste it from that comment.
SPOILER AHEAD!!!
he was human previously (very long ago) but after amon swallowed him and gave him his body and nain became a god and the dragon’s mate. however, he can die if he gets too depressed (not die but he’ll disappear from the world). that’s why there are the rituals that make him calm and lose his memory.
so basically, everything amon did to him is like for his sake (base on my understanding) and he actually loves nain too, but in his own way (yeah and in a crazy way lol) so in the end, all three of them got together. idk if this answers y’all questions but this is literally all i’ve got from that spoiler, sorry for the bad english too.
and alsoo… (spoiler ahead again)
amon don’t have any romantic feelings to the pink guy (base from the ppl who read the novel) i think it’s more of like curiosity??? (base on my understanding) and idk as to how all 3 of them gtg either, but i think im gonna ask questions again from them lol. but anw, i mean nain gets it. like, why chose 1 when you can have both?? KEKEKEKE
I read the novel! so I'll spoil how their relationship works as far as I remember so SPOILERS!
Na-in (mc) is in a relationship with both Amon and Gwen. The two MLs don't really like each other that way, it's more of a "tolerating their presence" kind of relationship. They accepted this dynamic cuz Na-in loves them both genuinely.
The MC was also at risk of disappearing completely from the world at that time if either one of them died (at least that's one of the reasons) they understand that both of them are equally important to the MC.

Can someone spoiler me a bit who will be the seme? Form the cover it's sha amon but I'm starting to get attached with the pink boy, don't want my hopes getting too far