Ao
Ao was born roughly five years ago when Satomi Rio saved Sousuke's life—but the cost was steep. The act split Sousuke's soul in half, creating Ao as a separate being. He carries their shared childhood memories, which is why the other Sousuke struggles to remember much of anything from back then.
On the surface, Ao seems pretty fixated on Shino. He's constantly messing with them, poking fun whenever he gets the chance. But fans often note there's probably more going on beneath that teasing exterior—it might just be his way of masking some real loneliness. After all, Shino chose to stick with Sousuke, leaving Ao on his own.
Content compiled by AnimeList.moe from publicly available sources.