Rio is Akari's brother. He's got a real weakness for attractive people and won't turn down a confession if someone catches his interest—but here's the thing, he's genuinely a good guy about it all.
Before their parents got together and actually made them siblings, Rio had developed feelings for Akari. Once they became family though, he had to keep it to himself. It's the kind of thing that just stays buried.
Content compiled by AnimeList.moe from publicly available sources.
