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This was supposed to be a romcom! Just how did this turn into a drama!? by Happypeppyreader
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)
04 Jan 2026
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Narnia Naberius has a clear objective: get access to the human child hiding in plain sight at Babyls. It is an affront to reality, that an insignificant, weak being has gone undetected for so long AND was actively concealed by high ranking demons on top of it! Hence he can’t just barge in and sink his teeth into his prey. No, he has to go a more delicate route about it. How to get around the Guard Dog, who guards his charges diligently? You distract him with a more pressing issue…
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The sleep of reason breeds monsters by Anonymous
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)
21 Dec 2025
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Collection of one-shots based on various ships following the prompts given by Dead Dove Kinktober 2025. Read the tags.
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babel hell by thosewhotrait
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)
10 Dec 2025
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Iruma's not exactly sure how he got here- sitting on his bed, naked, surrounded by four of his underlings- but he isn't exactly complaining.
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The Cerberus Inside by solis_solaire
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)
25 Nov 2025
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Iruma has been feeling odd lately.
It didn't feel like any ordinary ailment, but it was clear that he was seeing things. A shadow, out of the corner of his eye. One that when he stared, it stared back.
One that no one else could see except for him.
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El hijo del rey demonio by Rosaester15
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)
19 Nov 2025
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El legendario Rey Demonio Delkira desapareció sin dejar rastro, dejando atrás un trono vacío y un reino que aún lo espera.
Nadie sabe que su viaje lo llevó más allá del Reino Demoníaco… hasta el mundo humano.Allí, entre miseria y abandono, encuentra a un pequeño niño vendido por sus propios padres: Iruma Suzuki.
Un niño frágil, temeroso… y con una pureza que ningún demonio había visto jamás.Conmovido por su inocencia, Delkira rompe las leyes de ambos mundos y lo lleva consigo, jurando protegerlo.
Sin embargo, el antiguo rey no desea regresar a su trono, así que decide ocultarse junto al niño, criándolo en secreto bajo otra identidad.Pero los lazos de sangre y destino no pueden esconderse para siempre.
Porque algún día, el mundo demoníaco descubrirá la verdad:
el heredero del Rey Demonio ha llegado… y es humano. -
opera x kalego oneshots by pleb_moon
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)
26 Jul 2025
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I've only done the og universe oneshots, the other tags will be mentioned in other oneshots
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Apterous by hiiragi_jujika
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 Jul 2025
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Apterous (adj.) — Without wings, wingless
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What if Iruma-kun was biologically a Demon all along and he was intentionally grounded after all?
What if his biological parents are closer than you think?
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Xương rồng và chậu đỏ by canhat
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)
11 Jun 2025
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Opera đến chu kỳ ác và đồ chơi của ảnh 🐟 .
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Unholy feelings by Bondlessclown
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
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[...] “Ipse ven-” A hand rested on Kalego's left shoulder, claws clearly visible in the moonlight. "Hello there, Kalego-kun" the newcomer said. The purple-haired man tried not to lose his patience. He stood up, reached out with both hands to one of the two candelabras on the altar, and grabbed it. Just then he lost his patience and quickly turned around, holding the candelabra like a baseball bat. "At least let me finish my prayer, you fucking demon! What don't you understand about the "Vade retro Satana" part?!" Kalego shouted, pointing to where he knew the intruder's head was. The intruder used the hand on his shoulder to help themselves jump forward, landing on the altar. The demon turned around, and with their expressions unreadable as always, they said, "You should try to be less angry, Kalego-kun. All this stress isn't good for you". Kalego grabbed the wax candle and threw it at them, but it didn't hit them because the demon moved their head slightly"
Basically a Religion AU where Kalego is a human and Opera is the same as usual.
Series
- Part 1 of OpeKal/KalOpe
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tricycles can't have multiple third wheels by jellyruma
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)
18 Apr 2025
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Shichiro Balam, Kalego Naberius, and Opera have been close and decently affecionate for a while.
So close, in fact, that each one of them is convinced that they're third-wheeling the other two. -
How To (Not) Raise Your (Human) Demon Teen! by Meruruko
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)
27 Feb 2025
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(I'm terrible at thesd things ok)
Opera and Sullivan day-to-day with Iruma, Opera doesn't know how to deal very well with a kid -less with a TEENAGER- and Sullivan doesn't know how to treat a 14-year-old boy who isn't his student but his grandson -even tho Sullivan put himself in this situation-, this is a book of how these too adults try their best to make of Iruma a decent person
**in this AU, Iruma is slightly more rude than in the series but he's still our cinnamon roll lol
**none of the characters are mine, they're from Mairimashita! Iruma-kun -
A Demon's Warmth by Mewrlise
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)
26 Feb 2025
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Stay after class, I still hate you by Meruruko
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)
25 Feb 2025
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The youngest of the respected Naberius clan: Kalego, 14 years old, straight A's, perfect student, rank 4, future guard dog of Babyls. Basically, this boy is a completely Gary Sue in the eyes of the guys his age who know him.
Kalego's life is completely normal, for not saying boring.
Wake's up at 5, takes a quick shower, gets changed, has a light breakfast with refined food, checks his homework and goes to school at 6.
There's nothing weird with him, except that he's very strong and intelligent and all the things expected from a Naberius.Opera, 16, A.K.A the Top Dog, this kid is a mess. They used to be a stray until Sullivan adopted them 5 years ago after catching them in his garden stealing some fruit. They tend to skip classes and is always fighting with other students
Accidentally, Opera got confused with Kalego, so upper class students are now annoying Kalego. After solving the problem, Kalego noticed that Opera had...some kind of past time with bullying, mocking and teasing him, he had enough of that and today he's confronting them.
The character are from ‘Mairimashita! Iruma-kun, Kalego Gaiden’ they don't belong to me, support the og story and the spin off please.
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greed, gluttony and envy by inksmachine
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)
03 Feb 2025
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"You're 𝘷𝘦𝘳𝘺 greedy for a human," Leviathan comments offhandedly, watching Iruma scarf down meal after meal. He's like a bottomless pit. It's awfully... 𝘢𝘥𝘰𝘳𝘢𝘣𝘭𝘦.
While Sullivan-sama stiffens at the head of the table and Opera-san's ears flick with trepidation, Leviathan merely offers his plateful of food to a startled and terrified Iruma.
"Please don't eat me," the human begs.
"...I wasn't going to."
Or: Iruma is a greedy glutton with scars all over his body. This changes nothing and everything.
p.s i write when im high :)
Series
- Part 1 of earth bound
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【入間同學】【歐佩拉/卡爾耶格/巴拉姆亂燉】男惡魔的生理常識課 by rastar
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)
20 Nov 2024
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男惡魔的生理常識課
【入間同學】【歐佩拉/卡爾耶格/巴拉姆亂燉】男惡魔的生理常識課
原作：入間同學入魔了
作者：Rastar雷絲塔
分級：R18
配對：歐佩拉/卡爾耶格/巴拉姆，歐佩拉大總攻不當0，歐佩拉雙飛卡爾+巴拉姆，卡爾耶格/巴拉姆互攻
警告：3P，雙龍，雙飛，三明治，輪奸，男孕生子，產卵
提要：歐佩拉來找他的兩個小弟解決發情期。
設定：高階男惡魔可以使低階男惡魔懷孕，前提是受孕的那個很想生小孩。 -
King of my heart by kurenohikari
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)
16 Nov 2024
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If you had told Iruma that he would be living in the Netherworld a year ago he would have politely asked you if you were alright and needed help getting to the hospital.
He would have never expected to find his home between demons. He hadn't expected to become one of them either...
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What Ifs in Mairuma Alternate Universe by seereeus
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)
31 Oct 2024
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What if these really happened in another universe? What if these happened in the main story?
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Heat by Bondlessclown
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)
29 Sep 2024
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"No one would have ever thought that Opera, Sullivan's Security Devil, was a beta. The faint scent of their beta pheromones didn't mean much. And this bizarre common belief was of great use to the cat demon. Those who thought of them as an alpha, stayed away from them because they feared their strong territoriality and possessiveness. Those who thought of them as an omega, quickly changed their minds after having attempted a failed approach, returning to the idea of the somewhat atypical alpha. [...] Opera was truly, deeply a peculiar demon. Therefore, it was not strange that something else about them was atypical, not treatable in the same way as other betas. This did not discourage the red haired butler, who took the necessary medicines as needed. Until the need became daily, and nevertheless the relief was drastically decreasing"
Basically Opera is suffering from heat and they need a particular demon for relief.
TW: implied/mentioned grooming.Series
- Part 2 of OpeKal/KalOpe
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Inocente by WWBlair
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Manga)
14 Jul 2024
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Shichiro empieza a tener más confianza en sí mismo, eso no debería ser un problema en sí, pero implica que más personas se acercarán a él, lo conocerán y seguramente lo querrán apartar de su lado. Kalego y Opera acuerdan aceptar ese hecho, sin embargo, nada les impide exigir toda la atención que puedan de su amigo hasta que llegue el momento.
A veces las cosas no son complicadas, a veces las cosas funcionan y excepcionalmente, a veces todo sale sumamente bien…
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When it was? by Sweet_heart6687
Fandoms: 魔入りました! 入間くん | Mairimashita! Iruma-kun | Welcome to Demon School! Iruma-kun (Anime)
14 Jul 2024
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When did I lose you?
_You thought I was the only thing you wanted. I lost you, didn't I? Why? Why now? When was it?! Tell me!!_ I demanded, interrupting him without wanting to doubt him. I wanted to know now.
/What am I?/ he asked, looking at me fiercely for the first time. /What am I!? What place do I have in your life?! You say all that but you never decided who stays or who goes! You never decided, your wife or your lover!/ he shouted at me.
_I-
/Shut up! I chose! Only me!/ he demanded this time, getting up and slamming his hands hard on the table. /And I won't ask you for forgiveness for what I chose!! I did what you didn't and now I'm happy!!/
Series
- Part 4 of Heart of gold.