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Language:
English
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Published:
2025-04-17
Completed:
2025-05-02
Words:
14,324
Chapters:
12/12
Comments:
28
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96
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A Lunatic’s Lullaby

Summary:

Atsushi, a permanently tired college student and Akutagawa, a literal serial killer... MEET?!?! AND FALL IN LOVE?!?! PAINFULLY SLOWLY?!?!?! Yes pleaseee!

TW: Addiction, death, depression, abuse, suicide references (Dazai), gore/blood

Notes:

Kinda sorta based off of Sukunadaddy’s fanfic “That one time Fyodor fell in love with a serial killer” but not really cause I make it my own.

Link here: https://archiveofourown.org/works/64613014

(See the end of the work for more notes.)

Chapter 1: Atsushi's backstory time!!!

Chapter Text

This world was stupid. Completely, totally, and entirely stupid. Atsushi’s mom had paid his college tuition. That meant she had to be a pretty good person, right? Wrong.

Atsushi’s family is rich. Very rich. And they were pretty nice too... key word “were”.

Atsushi loved his dad, as most sons do. He played with Atsushi, took the family on vacations, and him and his mom gave Atsushi his precious little sister, Kyouka. She’s four years younger, has beautiful black hair that glows blue in the sun, and deep, blue eyes. She means everything to Atsushi.

But good things never last. In Atsushi’s freshman year of high school, when he was 14, his dad was involved in a fatal accident while he was driving home from the grocery store. Atsushi will never forget that day. Never.

Atsushi, Kyouka, and their mom were in the kitchen, singing along to music from the radio on the counter, and making dinner. They had been out of some sort of spice, so their dad had gone out to get it.

There was a knock on the door, they all look up from their cooking, their mom smiles.

“That must be your dad!” she exclaims.

“Why did he knock?” Kyouka asks.

“He must’ve forgotten his keys again!” Atsushi laughs.

He opens the door, seeing a man in a police uniform on the doorstep.

Atsushi’s mom and Kyouka appear behind him.

The policeman’s expression is somber, and he removes his hat.

“I’m sorry, Takehito Nakajima has passed away in a car accident. His address listed on his driver’s license led me here,” he said solemnly.

Kyouka comes up next to Atsushi, taking his hand. “Are you... joking with us mister...?”

“I’m afraid not,” he says sadly.

Atsushi’s vision closes in around him. His life flashes before him. Every smile, every laugh, every hug. Every single time his dad and him had interacted flashes faster and faster until he realizes he had sunk to his knees, tears running freely down his face.

He distantly hears his mom’s heartbroken screams of anguish, Kyouka is still loosely holding his hand, she’s simply standing stock-still. Rooted to the spot. In shock probably.

After that day, Atsushi and Kyouka’s mom slipped further and further into depression. She became addicted to alcohol, drugs, cigarettes, basically anything addictive had found its way into her possession and this point. And while being constantly under the influence, she became abusive. Lashing out in her anger at the siblings. Atsushi became responsible for Kyouka and his mom, making sure they both ate and stayed alive.

His mom quit her high paying job, but they had a lot of money saved up thanks to both her and their dad’s well-paying jobs. So at least Atsushi didn’t have to worry about money. He got a job working at a cafe anyway, because he was paranoid the money would run out.

He cooked and bought meals every night, and when Kyouka was old enough, she helped too. They both still went to school and got good grades. But Atsushi felt like he was failing.

As years passed, his mental health deteriorated. Atsushi was constantly stressed out, all the grief he never allowed himself to feel for his father was catching up to him, his mom’s unavailability was hurting more and more.

Their mom on the other hand, hated everything and everyone. She never once noticed her children’s stress or hard work; she just yelled and hit them every time she saw them. Kyouka had scars running up her left arm from when her mom cut her with a kitchen knife. After that, Atsushi had hidden all the knives in a locked drawer.

When Atsushi turned 18, his mom stumbled out of her room holding a cheap bottle of whiskey.

“Get out, I paid for college. Here’s your schedule and dorm room location. Get out of my sight before I kill you,” she said, slurring her words together.

Atsushi’s face pales. He knows he has to leave... but he can’t leave Kyouka! His mom weaves her way back into her room, slamming the door loudly.

Kyouka, sensing her brother’s pain, puts a hand on his shoulder.

“It’s ok Atsushi. I can take care of myself. You started caring for us when you were my age, I can handle it,” she reassures.

Atsushi doesn’t want to leave, doesn’t want to place that burden on her, but sighs.

“Ok... thank you Kyouka,” he hugs her.

That night, he goes up to his room and packs all his things in two suitcases. Clothes, toiletries, meaningful artifacts he’s collected throughout his life... If only he could pack Kyouka and take her with him... but alas, he cannot.

He tries his best to fall asleep, but mostly just worries about Kyouka that night. In the morning, he heads downstairs. He makes himself, Kyouka, and their mom breakfast.

Kyouka comes downstairs. They sit at the table and eat in silence.

Atsushi puts all the dishes away.

“I have to go now... school starts tomorrow...” he mumbles.

“Goodbye Atsushi! I’ll take good care of myself and mother, okay?” Kyouka smiles and hugs him.

“Thank you... goodbye,” Atsushi leaves. He gets in his car and drives to his new dorm.

(Guys idk how going to college works, please pretend this is accurate)

He groans, the stress of his life and this decision that wasn’t his catching up to him all at once.

Yes, he wanted to go to college... but he thought he would go later in life, so he could take care of Kyouka until she would be ok... But it’s ok. He’s got this.

He unlocks the door with a key, opening the door. He looks around. There are two twin sized beds, one on one side of the room, one on the other. One of the beds is covered in stuff and the shelves are filled with various items. The bathroom light is on.

Great.

Atsushi forgot that he was going to have a roommate.

He begins unpacking his own stuff, putting his clothes away and stocking his shelves with items, placing his own blankets and pillows and a single white tiger stuffie he’s had since he was a baby on the bed.

A boy wearing a loose white shirt and jeans comes out of the bathroom. He has striking orange hair, and he jumps when he spots Atsushi.

“Oh! You must be my new roommate!” he stammers.

“Yep. That’s me. I’m Atsushi Nakajima,” Atsushi says.

“Oh hi! My name is Junichiro Tanizaki,” he smiles. “Nice to meet you!”

“Yep, nice to meet you,” Atsushi responds dully. “Sorry, I’m tired,” he says when he sees Junichiro’s concerned expression.

Oh... Atsushi was going to LOVE college.