Muzan's Older Brother: Raising Kids Made Me Everyone's Beloved [Demon Slayer]

Ubuyashiki Asahi's greatest regret in life was failing to cure his younger brother Tsukihiko's illness and allowing him to become a man-eating demon.

To atone, he founded the Demon Slayer Corps despite his frail health, becoming its first leader and dedicating himself to destroying the progenitor of demons.

On the eve of his death, the Demon King who had once been his younger brother forcibly turned him into a demon.

"Now the same blood flows through our bodies again."

"Keep protecting me in Hell too, big brother."

Reborn as a demon, Asahi lost his human memories, and the mark of "Upper Rank Zero" was branded into his eyes.

Absentminded and forgetful, his only fixation is "raising his little brothers."

As the eldest son, he has to protect his younger brothers and cure their illnesses. He can't raise them wrong again.

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This is great, Muzan thinks.

Except his big brother can't remember people's faces and often mistakes other boys for his younger brothers, picking them up off the street and bringing them home to raise.

Until one day, his big brother brings home a boy named Yoriichi Tsugikuni.

Muzan: &^%#...

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A story about an absentminded but dependable demon big brother raising kids, healing their psychological wounds with love, and giving every poor kid without a big brother a happy home (not really).

The younger brothers he takes in include: Yoriichi (breaking up Yoriichi and Uta), Hakuji, Douma, Rui, Giyu (after losing Sabito), Muichiro (after losing his brother), and Zenitsu (the version hated by Kaigaku).

The eldest-brother group, who desperately want to be someone's big brother but end up being taken care of instead: Kyojuro Rengoku, Tanjiro, and Sanemi Shinazugawa.

Bitter orphan: Muzan.

Primarily a heartwarming family story about raising kids.

Yoriichi is the main pairing, though Muzan is also very important to the protagonist.

A healthy romance where both people save each other is lovely, but a twisted, gloomy brotherly bond is just so compelling.

Written for love by an overworked 996 wage slave. Updates whenever inspiration strikes.

Theme: Care for mental health.