Kuro is a junior high student who works as Ramune's assistant. He's got solid judgment and motor skills, plus a pretty rational head on his shoulders. The guy's got a serious poker face though—it's genuinely hard to tell what he's thinking or feeling, which means he ends up being the straight man to basically everything Ramune throws at him. Despite that dynamic, he trusts Ramune's expertise with mystery diseases completely. His rational mind and strong judgment are what keep things grounded when things get weird.
Content compiled by AnimeList.moe from publicly available sources.
