Noches

I think that Nain was the musician from 500 years ago that played the song for Amon. Amon most likely wiped his memory (why he did that possibly Nain didnt want to become some sort of God and wanted to die or Nain was sad of losing his freedom of some sort who knows) but he fell in love with the musician and wanted Nain remember who he was before (why he asked him to play). But unfortunately Amon cant have both cause he is an idiotic God.
The art could have been from that time and the child could have been Nain when he was reborn or a friend of Nain from that time.
Pink haired guy either is a magician from another time or some sort of time traveller cause it not adding up really.
The symbolism with the snake being Amon and the bird being Nain is crazy ngl.... literally just shows that Amon is a predator that doesnt really love Nain - he just wants to keep him captive.
Also I think that its that ritual is the one keeping Nain the way he is (not remembering his past self and still loving Amon even though he doesnt like what Amon does)........

Main character has the ability to partially read people's mind with visible text. He moved to the country side because its quieter there and it has less people with toxic text. He has the ability to clean someone's text like if they are thinking of murder, I believe he has the ability to alter their mind a bit. He gets sick if he cleans toxic text.
While getting his coffee beans, he get involved with some drugs, thats where he meets someone he cant read their text, a gangster. This has never happened to him. He becomes curious and the gangster guy is also interested in him. They start to develop a relationship. He later moves back to Seoul because he wants to be closer with the gangster guy and his other friend tells him he is wasting his gift. When he moves back, he meets the psychometric foreigner who has the ability to see the memories of objects he touches. Although main character is reluctant, he is forced to allow him to stay because he saw the memories of him doing stuff on his bed. Foreigner is main character's friend's step brother. It looks like main character and foreigner are involved with the police. The current case is with SAPA (the gang which the gangster is involved with). The Gangster seems to be an important individual of that gang, a right hand of some sort.

Hope that clears up the confusion