@missblueglasses there are a few characters you could apply it to, but there aren’t any romantic relationships, just kids crushing on each other. Hanako and Nene are the focus of the series, though.
@mip " Is there a harem subplot?"
Hmm no not really. There is a chapter where two girls are interested in Kabane, but one of them is a lot younger than him. The author definitely focuses more on Kabane's relationship with the other character.