@oliw from my understanding and perspective, seo was a serial killer who killed over 20+ men and ah-in is an orphan was living under the lie he was "blind" to recieve sympathy and pity from his clients, am not sure if he was a s worker or smth but seo (serial killer) booked an apointment w him under the impression he was blind, but he quickly figures out. from there it's murders and twisted love, from seo murdering ah-in's "bf" to creating serial killers who idolize and strive to be HIM, but the closet one to be similar to him also liked seo and commited murders until he ruined ah-in's vision, thats where ah-in became ACTUALLY blind and now its a series of seo killing and breaking his promise to ah-ain, but ah-in demanded that he loved seo and wanted to be by his side. little backstory to how seo became like this, seo had 3 mothers and his father SA him and breat him to death because he thought he was the devil himself, he was the reason one of his wifes or seo's mothers left because she was afraid of seo, why was she afraid? she saw him torturing a cat or a bird, that moment she never smiled at seo or ever liked him, which caused seo to be mad and told the father lies like "she was having an affair with other men" he punished her, giving her a scar and from that moment on, she ran away. seo continued living by being locked up in a basement and being beaten. until his brother from 2nd mother of his found him and confronted the father about seo, the father tried SA seo's brother but seo came in time to strangle him and locked him up in the basement and burned him, because the father thought "seo is afraid of fire so he wouldn't dare"
@♡+♡=♡♡ ah in pretended to be blind so he could work as a masseur, since only the visually impaired can in korea (to protect the client's privacy i guess), not for sympathy