Diagnosed by the Audience: Naoko is shown in flashbacks to have behaved in a consistently childlike and idiosyncratic way, even in the face of severe bullying, suggesting that she might be autistic or otherwise neurodivergent.
Naoko is liked for her really eccentric, insane personality and antics, in spite of the various atrocities she committed; overlaps with Creepy Awesome.
Same goes for Kazuya, after he becomes the Pumpkin King for the same reason.
Unintentionally Unsympathetic: The reader is clearly meant to sympathize with Naoko as she takes bloody vengeance on the people who so cruelly wronged her, and it might work if she was just killing them... but for many readers, the fact that she also gleefully slaughters any innocent person who gets in the way of her revenge makes her no better than any other slasher villain.
What Do You Mean, It's Not Political?: The likeness of Kuroki Tatsuo to Donald Trump can be interpreted by some people on certain sides of the political spectrum as being a metaphor about the person in real life for whatever reason, be it left-wing or right-wing. Yet his likeness in question seems to be cosmetic for the most part.
