He's Hijiri's baby, though she seems completely unaware of how genuinely weird he is. Everyone else definitely notices—and is honestly unsettled by him. The kid has an unnaturally deep voice for an infant, gets visibly excited watching people suffer, and demonstrates a creepy grasp of language that shouldn't be possible at his age. In the manga, he's even capable of stringing together full sentences packed with complex vocabulary. Basically, everyone except his mom finds him kind of terrifying.
Content compiled by AnimeList.moe from publicly available sources.
