YMMV / Sekai Oni

• Alternate Character Interpretation:
  • Just how much of a hero is Azuma by the end, or rather how much did she grow as a person? The question is a driving force throughout the entire story, and while we're shown her Lack of Empathy and her broken, childish understanding of the world around her, the story only ever affirms one thing: she doesn't even hesitate nor comprehend why killing off all of Maze to save her world is a bad thing despite everything she's been through.
  • Azuma's mother is a smaller case, given we barely see her. As far as the audience knows, she left Azuma in the hands of her brother's family, and is presumably unaware of how utterly fucked up their abuse is towards her. But then when she's finally shown, she either isn't aware of or doesn't seem to care about the fact that said brother and his entire family are dead. Even worse, in the final chapter, she handed off Azuma to someone else again and apparently even bought a small condo that was fit for herself rather than for her and Azuma, leaving it in the air whether Azuma got her Lack of Empathy from her mother or she was just super shortsighted about her own daughter.
• Complete Monster: The King of Maze is the sadistic mind behind the devils. Initially a baby forced to feel the darkness of the inhabitants of his kingdom, the King embraced the darkness, gaining enjoyment through the suffering of others and even his own, going so far to kill people from a prosperous district after discovering that they were happier than the rest. Continuing with the exploitation of the "Devils", actually Child Soldiers born to serve, and realizing that the worlds of Maze and Zera were going to crash, the King of Maze ordered the destruction of Zera, sending the devils to destroy it, causing multiple disasters, with the city of Buenos Aires being totally destroyed. Capturing the real bodies of the Cheshire Devils, the King promised to reunite one of them with her mother if she killed her "brothers", and after she did this, the King brought her to watch her mother's dismembered body. In the Last Night, the King created a shield using the lives of his people as fuel before becoming the World Devil, admitting that despite his initial claims, he really didn't care about the worlds, before trying to destroy the Earth in the name of darkness itself and his own entertainment.
• Nightmare Fuel: Holy mother of god, it's like if Silent Hill was blended with a battle shonen. From the sheer Fan Disservice of Kuroe and the (thankfully off-screened) sexual assault that Azuma's uncle commits to her, to the psychological reflections in mirrored surfaces and the sheer Heroic BSoD to spare for the entire cast, to the World Devils and the brutality a number of characters face in their ongoing battles. There's a reason why the manga is tagged as having psychological horror.