16 Works in Opera (Mairimashita! Iruma-kun)/Reader

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  1. chubby reader inserts. by

    Fandoms: 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia (Anime & Manga), Haikyuu!!, 呪術廻戦 | Jujutsu Kaisen (Manga), 呪術廻戦 | Jujutsu Kaisen (Anime), 文豪ストレイドッグス | Bungou Stray Dogs, Blue Lock (Manga), Blue Lock (Anime), 東京卍リベンジャーズ | Tokyo Revengers (Manga), 東京卍リベンジャーズ | Tokyo Revengers (Anime), Hunter X Hunter, Wind Breaker - にいさとる | Nii Satoru (Manga), Wind Breaker (Anime), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)  

    16 Nov 2025

    Tags
    Summary

    posts and fics i've made about chubby readers that are less than 1k words because of this they don't get their own separate uploads here.
    most of these chapters are around 500-800 words.
    more fandoms and relationships will be added in the future.

    Language:
    English
    Words:
    20,719
    Chapters:
    39/?
    Comments:
    40
    Kudos:
    829
    Bookmarks:
    68
    Hits:
    32,996

  2. Heated Need by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    03 Sep 2025

    Tags
    Summary

    The Sullivan Estate's hellcat is taking a vacation due to heat.

    Language:
    English
    Words:
    2,537
    Chapters:
    1/1
    Comments:
    4
    Kudos:
    8
    Hits:
    195

  3. Opera x Cat! Reader by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    26 Aug 2025

    Tags
    Summary

    Just a short, messy and fast paced fic that's been on my mind recently.

    Reader is gender neutral!

    Language:
    English
    Words:
    2,633
    Chapters:
    1/1
    Comments:
    4
    Kudos:
    9
    Hits:
    100

  4. Genesis by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    08 Jul 2025

    Tags
    Summary

    [Y/n] [L/n], a 14 years old girl, reincarnated in a fictional world that she used to watch? I wonder what could go wrong...

    Language:
    English
    Words:
    5
    Chapters:
    1/?
    Kudos:
    9
    Bookmarks:
    1
    Hits:
    182

  5. When The Devil Calls | WTDS! x Chainsaw Man by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), Chainsaw Man (Manga)  

    12 Jun 2025

    Tags
    Summary

    It’s already the end of the world for Y/N to get devoured by the very Hero of Hell…or so it seemed.

    Things took a turn when a bald old man had the nerve to form a contract with her as his…grandson’s babysitter?

    [WELCOME TO THE DEMON SCHOOL! IRUMA-KUN ! VARIOUS X DEVIL ! READER X CHAINSAW MAN ! VARIOUS]
    [CROSSPOSTED ON QUOTEV AND AO3]

    Language:
    English
    Words:
    58,511
    Chapters:
    22/?
    Comments:
    11
    Kudos:
    111
    Bookmarks:
    16
    Hits:
    4,904

  6. Who needs a right hand when you have a catboy??? by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    19 Apr 2025

    Tags
    Summary

    You wake up feeling needy. You have no qualms against waiting it out till you can steal away for some privacy... then you find out the hard way that demons sense of smell are particularly sensitive to human arousal.

    Language:
    English
    Words:
    2,548
    Chapters:
    1/1
    Comments:
    3
    Kudos:
    91
    Bookmarks:
    7
    Hits:
    940

  7. A Holiday Treat by for haliteisabasicsalt

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    19 Apr 2024

    Tags
    Summary

    Me and my friends are spiritual whores. Happy late holidays Halite. Enjoy this filthiness.

    Series
    Language:
    English
    Words:
    4,441
    Chapters:
    1/1
    Comments:
    3
    Kudos:
    62
    Bookmarks:
    3
    Hits:
    1,819

  8. Bake Date by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    07 Oct 2023

    Tags
    Summary

    Fresh from the human world, you can't help but feel out of place as the new lady of the manor. Far too used to having to take care of yourself and Iruma by doing everything from cooking and cleaning to working long hours in the hopes of giving him a better life, you felt rather disgruntled at having absolutely nothing to do. After all, your adoption into the Sullivan family meant getting a do-it-all family butler who refused to allow you to do anything even remotely based in those categories. However, in all these years you had actually grown rather fond of baking.

    And come hell or high water, you were going to enjoy the kitchen space again.

    Series
    Language:
    English
    Words:
    1,454
    Chapters:
    1/1
    Comments:
    8
    Kudos:
    114
    Bookmarks:
    10
    Hits:
    1,010

  9. All In Your Head by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    24 Jul 2023

    Tags
    Summary

    The reader is hit by a hallucination spell when fighting Netherworld beasts. When the reader's eyes land on other demons they can't help but mutter out apologies. Apologies for something that never really happened.

    Series
    Language:
    English
    Words:
    1,985
    Chapters:
    1/1
    Comments:
    3
    Kudos:
    64
    Bookmarks:
    8
    Hits:
    1,567

  10. An Unexpected Encounter by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    15 Jul 2023

    Tags
    Summary

    Student Opera working at a café. Reader is gender neutral.

    I'm not the one who wrote this fic, I just did some editing. The writer doesn't have Ao3 and gave me permission to post this. Follow them on tiktok @makodn

    Language:
    English
    Words:
    309
    Chapters:
    1/1
    Comments:
    1
    Kudos:
    37
    Bookmarks:
    1
    Hits:
    376

  11. At Home Relaxation by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    14 Jul 2023

    Tags
    Summary

    Your father (Sullivan) wants you to stay at home and relax. While him and Iruma go off to Babyls, you and Opera decide to have some fun!

    Series
    Language:
    English
    Words:
    2,871
    Chapters:
    1/1
    Comments:
    2
    Kudos:
    96
    Bookmarks:
    6
    Hits:
    2,485

  12. Evil Cycle~OperaxFemDemonReader by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)  

    19 Feb 2023

    Tags
    Summary

    While Opera is going through their evil cycle, you do your best to help them recover in any way you can.

    Series
    Language:
    English
    Words:
    5,430
    Chapters:
    1/1
    Comments:
    2
    Kudos:
    162
    Bookmarks:
    16
    Hits:
    3,640

  13. Welcome to Demon School Drabbles by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)  

    13 Dec 2022

    Tags
    Summary

    Collection of my WTDS Drabbles from my Tumblr

    Language:
    English
    Words:
    2,860
    Chapters:
    10/?
    Kudos:
    69
    Bookmarks:
    4
    Hits:
    1,445

  14. Wait. by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)  

    08 Mar 2022

    Tags
    Summary

    Synopsis: In which you fall sick and Opera takes care of you.

    Warnings: No particular warnings, but if you find interactions between an adult and a "teen" uncomfortable or weird you should probably dodge this. Not beta-read so it might suck oops.

    Disclaimer: I don't own Mairimashita! Iruma-kun and the characters.

    Language:
    English
    Words:
    6,219
    Chapters:
    1/1
    Comments:
    2
    Kudos:
    82
    Bookmarks:
    8
    Hits:
    1,688

  15. Demon And Human by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)  

    28 Oct 2021

    Tags
    Summary

    Iruma and Ryuka were both sold to the demon Sullivan by their parents.
    And thus, was taken into the nether world...

     

    To be the demon's grandchildren???

    What will happen to the siblings in the netherworld?
    Will they be discovered?

    Language:
    English
    Words:
    22,703
    Chapters:
    15/?
    Comments:
    7
    Kudos:
    99
    Bookmarks:
    25
    Hits:
    3,370

  16. Wild Cat by

    Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime), 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)  

    31 Jul 2021

    Tags
    Summary

    How you and Opera met and how they react to you being injure.

    Language:
    English
    Words:
    3,409
    Chapters:
    1/1
    Comments:
    1
    Kudos:
    158
    Bookmarks:
    10
    Hits:
    2,329

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