The body the MC reincarnates to is that of a prince who is seen as weak minded and submisse, as well as an alcoholic and sometimes annoying by the people who works for him.
Of course, this has a reason, it is all because he has been abused mentally and physically, raped and pretty much tortured by the king regent (the ML, oooh, I also want one just like that), to the point that every movement he made his body hurt like he was being stabbed (which the MC confirms it by, you know, feeling it now that he is in this body), and has wounds all over his body (only in places the clothes can hide of course). The icing on the cake is that the prince was a alcoholic because it was the only thing he could do to not feel the pain his body was in everyday and drank to numb the sensations until he gave up and killed himself (gee I wonder why). That's when our MC's souls enters the prince's body.
Don't worry though, now that the ML realizes the prince he used as human garbaged has changed (gasp), is another person (GASP) , with a fire in his eyes the real prince never had, he will treat him much better than before......
Like a toy (YES! A level up!)
An imprisioned toy only he can play with, but also can only got out when he feels like it. A toy that will be pushed and pulled until he fall in love with the male lead, because he is a nice guy.... (man, what a life, I am so envious)
The one I like the most is when the mother enter MC's room and she has a very bad face and the MC steps backs and starts to tremble scared, that was the only time in the story where he is like this towards his mother, THE ONLY TIME, and she's supposed to be a manipulative and abusive mother, but throughout the rest of the story he doesn't even show how f***** up was their relationship, he only tell us, but it doens't amount to nothing (except this one time)
Also anothe thing that I liked is how you discover that the ML lead was also thrown away by his real father and now the father apparently is trying to reconnect with him because he needs him for shady reasons, just like what the MC suffered. It's a nice touch to show how alike they are, simple but effective.