Week 72! (Patreon)

Lupin being into cooking has been more of a "recent" development to his character, although it's become more important to him as time has gone on as well. It was actually first mentioned in the comic 017 - Challenge Accepted, or rather, in the RGC info underneath the comic, but its first appearance in the comic itself was Arc 10.

A big part of expanding upon this little detail thrown in early on really was to expand on Lupin's character in general. In the Old Canon, he was really only meant to be a very standard stereotypical bully, since the Old Canon was a much more traditional and intentionally-cliche high school story. In the New Canon early on, I seemed to happen to intensify those traits even further, to the point of having Lupin actually punch Kale in the face rather violently. I found myself disliking this direction a lot as time went on, since Lupin was more of a prop without any real character beyond his stereotype. This is why Lupin has seemed to "mellow out" a lot over the course of the comic after that second arc, changing from being constantly loud and almost-sadistic to being far calmer and more controlled. In-canon you could say that what he talks about with Bruce at the end of Arc 10 had a hand in calming him down. The addition of liking to cook gives him an extra unique trait to help him stand out more and be an actual person.