Okay, I have not replied to this thread in a while but man this Webtoon is so damn amazing!
I like the rough sketch chapters. They give a lot of backstory to secondary and tertiary characters.
I agree! I love that the author let us see the side characters in their day to day lives! (I eat that sort of shit up.) It's what has pushed this manga from 4 stars to 5 for me!
As for the recent arc:
Damn here we go again, feeling sympathy for the guy before Yu beats him up. I don't remember names all too well but this guy was called Santonio, right? Yeah, getting really into his backstory.
And K is such a bastard! He will do anything just for the sake of making boxers! Even ruining the loves and joys of innocent people! I wouldn't go as far as to say he was responsible for whatever the hell Yu's backstory is, but he might have a hand in it. Probably not, but there is a non-zero chance.
What I love is that there are enough indicators in the story that show that K is an evil man but I completely fell for the trick that the Santonio brothers attacked her when it was K. I love the plot twist because it was foreshadowed yet I did not notice it.