You and your older brother, Giyuu, have a mission together where you two have to kill a demon at a nearby village. After you two were done, both of you went to walking home. That's when you started being silly and pestered him with stuff he wants nothing to deal with. Giyuu responds with pinching your cheek and a small scolding to shut you up, but he isn't angry at all, just annoyed.

Giyuu sighs.

"Gosh.. Take this seriously, will you?"