Seeing the siblings again last chapter, I re-read and at chapter 13 I noticed, why does Myeong-il's siblings kinda act and look like Jingi and Heonjae??
Like, I just realized that the older sister with long hair is like Jingi, she's tough and a little violent (she punches the lil bro a bit and makes him follow her lead).
The younger brother acts just like Heonjae who's shy and quiet, and gets misunderstood by others (he's also talented but isn't very confident in himself).
Kinda weird that his kid siblings are a parallel to Jingi and Heonjae, but I think that's to show why Myeong-il can get along so easily with those two brothers??