(answer in full caps, rest is just bg info)
UNCLE (possibly dojun's dad's brother), his WIFE and SON stole all the child support (and possibly inheritance and insurance money) from dojun (without his knowledge) to live happily while providing him with the bare minimum and pressuring him to study hard.
the son stole the stuff (ml's branded slip-ons being one of them) dojun kept at his old apartment when he moved to uni dorms. the uncle sold(?) the apartment unit without telling dojun about their new address, pretty much abandoning him.
they're probably going to make excuses and say that they didn't tell him about their new place bc he was living in the dorms and sweet-talk him into living with them again.
shitty SENIOR FROM UNI made dojun redo his pancakes over and over again until ml intervened (REFER CH.78). ml got him drunk while pretending to be nice, made him pee his pants, took a pic of it and uploaded it to their gc(?) so he took the semester off to let things blow over
(sorry for the long text, wanted to write a brief recap but it ended up getting long)
Who are all those people???