Not really, but it would help contextualize the character arc of the MC. You can still get an idea of who he is without it, but it grounds it a bit more. (It's also a beautiful read.)
I just read ch.30. So basically Gwen is interested in Na-In because he is Amon’s possession? It doesn’t have to be Na-In? Are we going to have further explanation later?
The plot twist
So the one who was bullied during their high childhood days was Yuwon, but he thought it was Dohun?
yes