There's a Rat in Our House - Vol. 1 Ch. 25

[MangaDex]

 

[EchoGirl]

i guess she would have a spare key but i'd still be hesitant on someone coming in and outta my place (then again i guess those korean doors have number codes instead of physical keys)

"i'm not a child" well he is younger but even adults have to be cared for as well. tho wonder if there's versions of similar stories where someone like the mc would take in a younger person without it being some sexual relationship