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My Next Life as a Demon Slayer: All Routes Lead to Obsession! (Reverse Harem Yandere Demon Slayer x Reader)

Summary:

An 18-year-old Demon Slayer fangirl, reincarnated with a obliviousness, desperately tries to avoid death flags, only to unintentionally charm every eligible male into a possessive yandere obsession, intensified by her unwitting power to make them dream of her in the most intimate ways.

 

YN’s personality is inspired by Catarina Claes from My Next Life as a Villainess: All Routes Lead to Doom!(I watched the anime and basically couldn’t stop thinking about her energy.)

Chapter Text

Background Information:

1. The Reader (Y/N) Profile:

* Name: (Y/N)
* Age: 18 years old
* Personality: Reincarnated fangirl with a Catarina Claes–inspired personality (My Next Life as a Villainess, I watched it and got way too attached to her vibe lol). This means she is:
* Oblivious to Romance: Cannot recognize romantic or sexual advances, even when blatant. Interprets everything as friendship, concern, or general goodwill.
* Kind-hearted & Empathetic: Genuinely cares for others, always tries to help, and sees the best in people (even Sanemi and Muzan at first).
* Clumsy & Accident-Prone: Frequently stumbles into awkward situations, which somehow always leads to unintended close contact or “save-the-princess” moments.
* Doom-Flag Focused: Her main priority is survival. She actively tries to avoid every “bad ending” she remembers, though it often backfires and pulls her deeper into danger.
* Pure & Innocent: Despite the mature world around her, Y/N remains completely untainted by malice or awareness of romantic tension, which only makes her more dangerous to everyone else’s sanity.
* Appearance: Left to the reader’s imagination, but generally perceived as soft, endearing, and naturally attention-grabbing.

2. The “Unintentional Dream-Smut” Ability:

* Nature: A subconscious, passive ability Y/N is completely unaware of.
* Mechanism: When someone feels intense desire, obsession, or fantasy toward Y/N, her subconscious essence manifests within their dreams.
* Content: Extremely vivid, often explicitly sexual dreams tailored to each character’s personality and desires (e.g., Zenitsu’s are desperate, Sanemi’s rough, Giyu’s quiet and possessive, Muzan’s cold and dominant).
* Impact on Characters: These dreams feel real enough to blur fantasy and reality, intensifying obsession and making their feelings for Y/N feel “destined” and undeniable. It accelerates yandere tendencies and heightens emotional instability.
* Impact on Y/N: None. She remains completely oblivious, only noticing that everyone around her is acting increasingly strange or flustered.

This story was mostly for fun after I got an inspiration. Characters might be out of characterization.

The main tone of the story kinda might change throughout, depending on how I want the story to go.