Fanfic / The Otsutsuki Demon

The Otsutsuki Demon is a crossover between Naruto and Demon Slayer: Kimetsu no Yaiba by Wararabihime-rian on Wattpad.

After Kaguya Otsutsuki is sealed by Naruto and Sasuke, she finds herself in the body of Nezuko Kamado. Adapting to her new body and life alongside Tanjiro, she now has to learn how to conquer the sun and prove herself to the new world she is in.

The author wrote a sequel entitled The Story Continues that featured a crossover with My Hero Academia that later shifted to Percy Jackson and the Olympians but was deleted by the author after they expressed dissatisfaction with the direction it took, later rewriting it once more to focus solely on My Hero Academia. The story can be accessed here.

Beware of unmarked spoilers for Demon Slayer

The Otsutsuki Demon provides examples of:

• Abled in the Adaptation: Oyataka is cured of his curse by Kaguya after Muzan's defeat and regains his sight
• Adaptational Nice Guy: In canon, there was zero indication that Kaguya particularly cared about other people other than herself and her sons. Here, she at least regrets Unpersoning Nezuko after finding herself in the latter's body and cares about her adopted children
  • The Upper Demon Moons are a collective example thanks to Kaguya's Positive Friend Influence after she adopts them as her own children, not least because of her authoritative parenting style that balances love and strictness in perfect equilibrium
• Asshole Victim: Daku's unnamed mother was most certainly a terrible parent to him, so her death isn't exactly mourned by everyone when Kaguya kills and cannibalizes her
• Back from the Dead: Kaguya resurrects the loved ones of all of her adopted children after Muzan's defeat, such as Kanae, Kotoha, Koyuki, and Yoriichi among others
• Because You Were Nice to Me: The Upper Demon Moons defect from Muzan because Kaguya treats them with actual love and doesn't view them as expendable
• Benevolent Boss: Compared to Muzan, Kaguya is much nicer to her subordinates and genuinely cares for their well-being
• Beyond the Impossible: Kaguya is able to walk about in daylight despite her demonic nature, which proves crucial when Muzan orders Nakime to kill her via sunlight exposure in their battle
• Doting Parent: Kaguya dotes on all of her adopted children like they're her own kids
• Due to the Dead: Susamaru receives a proper burial from Kaguya and Tamayo after Muzan's curse kills her
• Even Bad Men Love Their Mamas: Douma, for all his sociopathy, views Kaguya as his own mother and is not pleased when Muzan calls her a bitch
  Muzan Kibutsuji: (to Kaguya) You bitch...
  Douma: Oi! Okaa-san is not a bitch!
• Happily Adopted: Exaggerated when Kaguya adopts all of the Hashira and Upper Demon Moons, and they're totally fine with it
• Heel–Face Turn: The Upper Demon Moons ditch Muzan thanks to Kaguya's Positive Friend Influence
• I Just Want to Be Loved: Kaguya's reason for adoption hinges on her past experiences with Hagoromo and Hamura from her old life
• Let Them Die Happy: Kaguya promises to Susamaru that she will be there for her in the next life in the latter's dying moments
• Make Them Rot: Kaguya initially attempts to permakill Muzan by stabbing him in his last remaining heart with an Ash-Killing Bone. She elects to simply decapitate him with her sword after she finds the disintegration process too slow for her tastes
• Mama Bear: Kaguya, in spades
• Outside-Context Problem: Let's just say that Muzan's plans are completely derailed with Kaguya's arrival in the world of Demon Slayer and leave it at that
• Spared by the Adaptation: Rengoku is not killed by Akaza during the events of the Mugen Train arc since Kaguya takes the hit for him, though he receives injuries that temporarily prevent him from serving as Hashira that she heals shortly after
  • By extension, none of the Pillars or the Demon Moons die since Kaguya kills Muzan and ends their conflict
• Taking the Bullet: Instead of Rengoku who is impaled through the stomach by Akaza, it is Kaguya who gets hit
• Wrong Context Magic: Kaguya's chakra and Otsutsuki adaptations effectively make her a god in the world of Demon Slayer: Kimetsu no Yaiba