Headcanon That The Tiger Causes Atsushi To Consume More Calories/energy Doing Literally Than Normal People

everytime chuuya's ferret sees atsushi, it gets scared; chuuya reassures atsushi that its probably just becuz he's not used to him or maybe becuz atsushi's ability is a tiger and its confusing the ferret but when chuuya isnt looking atsushi makes sure to stare down the ferret so it Knows that it once was atsushi's afternoon snack.

hc that atsushi finds the nearest soft item and starts kneading it with his hands when stressed because it calms him

“over and over, all born into great pain” — bungou stray dogs — chuuya, atsushi, dazai

“Atsushi appears on Chuuya’s doorstep covered in blood and full of drugs. Dazai, despite not being present, dutifully haunts the narrative. or: Strangers who’ve been shaped by the same person. or or: 4,000-ish words of musing and vibes and no plot.” — posted for @dazaibirthdayweek2024 !

words: 3,925

first published: 6/18/2024

characters: dazai osamu, nakahara chuuya, nakajima atsushi

relationships: nakahara chuuya & nakajima atsushi, dazai osamu & nakajima atsushi, nakahara chuuya/dazai osamu

tags: mild hurt/comfort, light angst, introspection, no plot/plotless, implied/reference drug use, non-consensual drug use (off-screen), mild gore, tiger nakajima atsushi, implied/referenced cannibalism (crazy), caring nakahara chuuya

crossposted on ao3

Dazai’s stupid kid is crumpled on Chuuya’s doorstep.

Chuuya had wanted to head down to the liquor store. Instead, his boots hit boy as soon as he stepped out the door. Fucking Dazai, Chuuya thinks, because it must be Dazai’s fault.

Chuuya sighs. He turns back to his empty penthouse, as though expecting Dazai to pop out from behind his couch and shout surprise! then announce to him some stupid plan that absolutely necessitates the weretiger bleeding out in the hall.

“Weretiger,” Chuuya says. The weretiger gives a noncommittal grunt. Copper is already filling the air and seeping into the carpet from a wound that must be in the kid’s torso, way he’s doubled over it. God, the stain in the carpet. Chuuya should just get the carpet ripped out, with how often he has to call the cleaners. Doesn’t the kid have superhuman healing? Chuuya squints. Shouldn’t he be healed already?

“Weretiger,” Chuuya says again. The kid’s shoulder shifts a centimeter and that’s about all the response he gets. Well, okay. Questions later. First things first — the weretiger rises into the air and floats into the middle of the living room. His eyes flutter, but he doesn’t seem to register the red glow around him.

“Bwuh,” the weretiger says. A conveniently stashed sheet of plastic (this is not Chuuya’s first rodeo) lifts up and settles over the couch cushions. The weretiger follows. “Bwuuuhhgggg,” he says smartly into the plastic. His left arm is a long pale line hanging off the couch, which Chuuya’s black Maine-coon is already clawing at. The weretiger seems unperturbed by this.

“Uh-huh.” The first aid kit deposits itself into his hands as he strides over to the couch. “Lemme see that wound.”

Except there’s nothing to see. Under the ripped up shirt and all the clotting blood and bits of loose flesh, it’s just smooth skin. So his ability has done its work, if belatedly. Some of this blood is only a few minutes old. It healed fast, but not as fast as it ought’ve. But the weretiger is still acting all loopy, whimpering like something hurts. Just blood loss? That doesn’t feel right.

Chuuya sits himself on his coffee table, knees bumping the couch. “What’s your name again?” It’s somewhere in the back of his mind, but all he ever hears is Akutugawa’s jinkos.

“Naka…” the weretiger starts, then seems to forget he was saying anything. He turns to the cat as though he only just realized she was drawing tracks down his arm, and coos, scratching at her chin. His pupils are huge. Ah, that’s one question answered at least. A hard drug hindered his healing — and it would have disoriented him enough to panic, go out searching for help. Now the question was what drug, why, and how the fuck did his mind, even drug-addled, end up at Chuuya?

“Naka…” Chuuya echoes, scratching his chin. He really should know this, considering the scuffles and the bounty and the general hot topic the boy was around the Port Mafia. The weretiger does not provide any more help. He is entirely caught up with the cat. Now fully turned onto his side, the weretiger has both hands around the cat’s face, scratching dutifully under both her ears. She purrs like a motorboat.

“Hello,” he says reverently. Big-eyed, he tilts forward until he and the cat can touch noses. When he smiles Chuuya catches braces and grimaces. “Hello, hello, meow.”

“Mrow,” the cat offers.

“Nakajima!” Chuuya finally settles on, triumphant. Nakajima looks up at him fully for the first time, grinning with a Dazai-like edge. Well — tree, apple, falling, etc. Chuuya supposes he’s not so much grinning like Dazai as he is grinning like someone high on nebulous hard drugs, which Dazai often is.

“What’s her name?” Nakajima asks, glossy eyes settling somewhere on Chuuya’s chin.

“Pingus,” Chuuya says, and Nakajima dissolves into giggle fits. He rolls over, pushing himself into the back of the couch, giggling so hard his feet kick out. Pingus, scandalized, climbs onto the couch and begins kneading at Atsushi’s side, trying to force her head under his hands. “What!” Chuuya says, even though he’s listened to a hundred people laugh at his cat’s name before. “It’s a fine Spanish wine, Nakajima, does your idiot mentor teach you anything—”

Nakajima’s laughter stops abruptly. Everything about him stops abruptly. He pushes himself up onto his forearms and Chuuya realizes he hates the sight of him — collapsed on Chuuya’s fine couch, which he’d bought with blood money; white hair and moonlight skin and tatters of a white shirt, all matted and sticky with his own blood, bits of flesh trailing down his stomach. He’s got, Chuuya realizes, red smears all over his chin, his neck, and if he opened his mouth a little wider it might be on his teeth, too. Chuuya had always thought the kid sweet, a bit naive, earnest and reckless. Akutugawa had called him a stupid dog. He wonders about the man-eating tiger stories; wonders what Dazai saw in him in the first place that he thought would make a good partner for Akutugawa. He wonders what Dazai’s taught the kid - what he’s nurtured in him.

“Dazai,” Nakajima says, just as reverential as when he’d been speaking to Pingus. “Dazai told me to come here.” Out of his front pocket, he pulls a crumpled, slightly damp piece of notebook paper and holds it out to Chuuya. He grins big, proud of himself.

A safe place in case of emergency! :D It reads, in Dazai’s stupid messy scrawl. Chuuya will be kind and keep Atsushi for a bit. Tell Chuuya Dazai sent you!

Below these instructions are Chuuya’s address, his phone number (Jesus, Dazai, Chuuya thinks — might as well start plastering Chuuya’s face all over Main Street), and, of course, nothing directed at Chuuya.

Chuuya sighs, runs a hand through his hair. Fucking Dazai — what was he thinking, sending Nakajima his way? Did he tell his whole gaggle of do-gooders Chuuya’s place was a safehouse? And why the hell would he send Nakajima straight into the Mafia’s hands?

(Unless, of course, he believed Chuuya would decline to tell the Mafia about this at all. It was a big risk, believing that.)

“So.” Chuuya leans forward, bracing his elbows on his knees. He studies Nakajima, whose chest is heaving, every breath coming with a hint of a wheeze. Did he overdose? Chuuya taps his foot, considering — he has aspirin in his first-aid kit. Narcan too. “What happened, huh? Too much catnip?”

Nakajima grins lazily (yes, he was right — blood and braces), head lolling against the couch. His arm is limp when Chuuya picks it up, presses two fingers to the pulse point at the inside of his elbow. Nakajima’s offering way too much trust, either because of the drugs or Dazai — Chuuya could stop his blood from flowing at all, if he wanted to. But Dazai would shoot him in the temple, probably.

“I dunno,” Nakajima slurs. His mental condition is definitely unnerving, but at least his pulse feels fine, and his skin isn’t clammy.

Chuuya pinches his inner arm and Nakajima yelps, jolting — his arm becomes monstrous and heavy. Chuuya stares at it, considering the length of its claws. Man-eater, he thinks.

“Huh,” Chuuya says. Then: “Wake up, kid. Tell me what happened.”

“Um.” Pingus is rubbing her face all over Nakajima’s jaw. A deep purr rumbles in Nakajima’s chest to match Pingus’s, which Chuuya is only mildly surprised by. There’s some semblance of awareness in Nakajima’s eyes that Chuuya thinks is due to Pingus’s bothering. She’ll get extra fish with her dinner, as a reward. “Dazai and I were undercover…” Nakajima’s eyes roam the ceiling, running his (both now human, thank God) bony hands up and down Pingus’s back. “Undercover, and… Dazai told me to leave — really fast.”

“Why?”

Nakajima looks frustrated, and Chuuya understands. With a mind addled like his is, it can be hard to put words to things even if you know exactly what you’re trying to explain. But if there’s trouble, there’s no time to wait for Nakajima to sober up.

“Because…” Nakajima says, “He said we were drugged… we were at this fancy party, and I started feeling funny, and Dazai said, go to the Agency, but the Agency was far away… I left him there…” Nakajima jumps up, suddenly, throwing a yowling Pingus off his chest. White knuckling the back of the couch, Nakajima shouts, “Dazai’s in trouble!”

“Calm down.” Chuuya considers reaching out, pushing Nakajima back down onto the couch. That probably wouldn’t go well. “You know Dazai’s fine.” Fine was maybe a strong word, but alive was a fact that seemed to stay true no matter what. “I need more from you. How’d you get injured?”

Nakajima blinks at him. “Injured?”

“Injured,” Chuuya reiterates, pointing at the chunk of yellow fat smeared across Nakijma’s stomach. What a fucking sight. All the hallmarks of a corpse on his couch, except the actual injury.

“Oh,” Nakajima says, squinting down at his own blood. He sort-of snarls as he runs his tongue over his upper teeth, like he just realized the blood on it. “I don’t — remember? I think someone tried to stop me leaving…”

Chuuya puts the images together. Thinks it through — Nakajima and Dazai, both of them completely out of place in some party full of cocktail dresses and tiny sausages. The drugging had to be well hidden for Dazai not to notice, but he would have known the second it slid down his throat. He imagines Dazai’s panicked face — the one no one else ever notices except Chuuya, who is very well attuned to the tiniest twitches of Dazai’s eyebrows — imagines him calculating exactly how many minutes him and Nakajima had, making an estimated guess based on Nakajima’s size and ability and how much he’d unknowingly chugged, and then deciding the kid had enough time to get the hell out of dodge.

Nakajima would have had to leave as discreetly as possible, as though he didn’t know anything was wrong. But if someone had drugged them both, then they were watching them, too. Nakajima had been intercepted, gotten hurt, and — hm. The man-eating thing had only ever been rumors. But if he had claws like that, Chuuya could only imagine the teeth, and what one does when there’s an unknown drug and panic and blood loss all settling in at once. With his efforts to get all the blood off his teeth and out of the crannies of his braces, Nakajima is making a lot of funny faces.

So someone was probably dead. And Dazai was God knows where. And — okay.

Chuuya tilts his head up to the ceiling, ignoring Nakajima, who has once again become preoccupied with Pingus. Question time:

1. Where’s Dazai? Did he get himself out too? Or is he drugged up in someone’s basement?

2. Why Nakajima and not him? If it were one or the other, Dazai would have had a much easier time getting himself out than Nakajima. His tolerance is higher, he probably had less, and, frankly, he’d probably be much more useful in terms of knowledge.

3. For that matter: why not both? Why couldn’t both of them leave? Scratch question 2, then — the only reason Dazai would let himself get caught is if he had a reason to.

4. Fine then, last question, besides why come to Chuuya: how long should Chuuya wait for the stupid mackerel to show his face before he sucks it up and calls the Agency?

Hopefully, he won’t have to deal with the last question. Either Nakajima sobers up soon or Dazai escapes. It’s been a few years and Dazai’s gone weird and soft, but at the very least he should still be totally capable of escaping some stupid fucking kidnappers.

Chuuya should probably add who drugged them to his list of questions, but that’s not really his problem. With the story straight-enough in his head, he just needs to focus on getting Nakajima sober. By the state of the kid’s giant pupils and still-heaving breaths and incessant giggles every time he whispers Pingus to himself, it’ll be a while.

Babysitting duty. Ah, well — Chuuya’s used to babysitting duty, ever since Dazai fucked off and left the Akutugawa kids reeling and helpless. (Not that either of the kids would admit that’s what happened.) Dazai was always leaving him on babysitting duty.

Chuuya sighs, stands, retrieves a blanket. By this point Nakajima’s sunk back down onto the couch, holding a loaf of Pingus against his chest. “Rest up, weretiger,” Chuuya says, throwing the blanket over the both of them. He’ll wash all the viscera and shit off the blanket later.

Nakajima, covered up to his nose, blinks with those big, dual-colored eyes. With a little mrow, Pingus’s head pops out of the blanket and she starts nuzzling Nakajima’s cheek with his nose.

“Are you gonna tell Akutugawa I’m here?” Nakajima asks softly. It should be a question asked with fear, but it’s awfully bland — unafraid. Chuuya’s lips twitch.

“No,” Chuuya says, and heads into the kitchen.

Dazai used to do a lot of cocaine.

He probably doesn’t anymore. Or he’s really good at hiding it. Chuuya doesn’t imagine a cocaine habit would go over well with the detectives, and he doesn’t imagine Dazai could even hide something like that from the smart one. (From the others, he could definitely hide it. But not the super smart one.)

Chuuya’s done it a few times himself, but it’s never been his preference. The dignity of alcohol, the richness of it, and most of all the beauty of it — all those fine, expensive, aged bottles sitting on his shelves — has always appealed to him. But Dazai liked the way things like cocaine got him excited, amplified his mania. He liked uppers, from cigarettes to ritalin to coke, because they made him feel human.

Not that it’s cocaine, Nakajima’s got in him. It’s definitely not cocaine. It was probably ketamine or benzos, an attempt to make Nakajima all loopy and relaxed and weak. That’s not what happened, clearly. At least it’s not what happened immediately, because Nakajima had enough strength in him to escape an attacker. Must’ve been his ability slowing the drug.

It doesn’t matter. This is all to say that Chuuya has more than enough experience sobering himself and others up. He sets to work frying some eggs.

Nakajima’s not asleep; from the other room, Nakajima’s quiet voice wafts in, indistinguishable murmurs interspersed with giggles and Pingus’s mrows. At some point he starts humming a song which Chuuya has to strain his ears to hear. It’s a sweet, lilting melody — his brain fills in the lyrics instantly and his heart twists at the realization that it’s Dazai’s stupid song, can’t do a double suicide alone.

Chuuya slides the eggs off the pan with his spatula and sets them gently on the plate. Then he stops there, stares at the eggs, the shaking yolks. Thinks about being fifteen in Mori’s office, glaring at Dazai, the feeling in his gut that something horrible had changed in his life. Thinks about the stark red marks of Dazai’s hand on Akutugawa’s cheek. Thinks about childrens’ feet pattering softly down the halls of the Port Mafia’s safe houses and headquarters’ halls. Thinks about Nakajima, smiling at Dazai’s name, singing silly tunes Dazai taught him.

Toast pops out of the toaster. It’s a little burnt. Chuuya blinks and takes a breath that does not shake. He flicks on the radio — some public station playing soft jazz — and he can’t hear Nakajima anymore.

When Chuuya returns to the living room with two ham egg and cheese sandwiches, Nakajima pops fully up, although this time he holds Pingus to his chest so she doesn’t fall. The blanket falls, though, and it’s the same as it was before: the remains of a nice shirt falling over thin shoulders, drying brown blood splattering his stomach and chest and arms, his own fucking skin and flesh and fat stuck to him. Chuuya’s seen gore before — seen it a thousand times worse than this — but something about the sight has him keeping his eyes dutifully on Nakajima’s forehead.

Nakajima devours the sandwich in practically one bite, his jaw wider than it ought to be. Chuuya pretends not to be unnerved by this.

Once Nakajima has fully chewed his sandwich and patted his stomach and hummed his thanks, Chuuya asks, “Feel any better?”

The penthouse is cold. Chuuya likes it that way. But Nakajima shivers, pulling the blanket back up, tucking himself back down onto the couch. “A little,” he says, suddenly very childlike. As though he’s only just realized he’s cold (likely, considering what some drugs can do to one’s awareness of things like temperature), Nakajima curls more and more into himself on his side, pulling the blanket up his face. Ridiculous, that he’s on Chuuya’s couch right now. Ridiculous, that Chuuya doesn’t call Akutagawa. Fucking Dazai.

Chuuya stands abruptly. Nakajima blinks in response.

“Rest,” Chuuya says again, then promptly retreats to his bedroom.

Dazai is sprawled out on Chuuya’s bed, twisting the soft black covers beneath him, hair fanned out over the pillow. He’s got a few bruises on his cheek but there’s no blood, Chuuya recognizes first, then recognizes second that Dazai is on his fucking bed.

“Jesus fucking Christ,” Chuuya says. Throws his hands up in the air, lets out a noise like a yell without any air — makes a scandalized face that Dazai only blinks at, throws his arms back down, then towards Dazai, into the air, then out, gesturing widely at the room around him. Every loose object in the room raises about a centimeter, drops, raises. “When the fuck did you get here!” He crosses the room in two long strides, pulls the lounging Dazai off the bed by his shoulders, and shakes him. “Your stupid kid is high out of his mind in the living room!”

Dazai groans, fake, squeezing his eyes shut. “Chuuya, Chuuya,” he whines, putting on a strange voice like a telenovela housewife, “Chuuya, my head is killing me!”

“You’ve done worse drugs,” Chuuya says, but he brings up a hand to start prying Dazai’s eyelids open and check his pupils. Yelping, Dazai bats him away, wiggles out of his grip, then rolls floppily onto the other side of the bed. He pats the space next to him in invitation.

“Fuck you,” Chuuya says.

Dazai just frowns.

The window is open, Chuuya realizes, a breeze fluttering the blackout curtains. This is somehow an even worse realization than finding Dazai on his bed, and Chuuya has to fully turn on his heel so he’s facing away from Dazai. He grabs his face in his hands, bounces on his heels once, twice, thrice. The idiot had either broken into the apartment below and climbed up to the penthouse or started from the roof and climbed down — either way, it’s so ridiculous and unnecessary that the thought of it gives Chuuya heart palpitations.

“You have a key to this apartment!” Chuuya hisses, although something about it feels like he shouldn’t say it out loud, like it’s an admittance. “Why would you-!”

Dazai hums in a way that tells Chuuya he won’t get an explanation. Either he’d done it for fun or done it because it was all part of some stupid plan or mind game or manipulation. Chuuya decided he didn’t care, because the more pressing question was—

“Why would you give that kid my address?” He steps forward so his knees are bumping the mattress.

Doe-eyed and innocent, Dazai stares up at him. “Why wouldn’t I?” He asks, “Chuuya is a good babysitter…”

“I’m going to kill you,” Chuuya says, but he doesn’t add his usual violence to it because he’s squinting at Dazai’s pupils. Blown pupils, but his cheeks are a normal warmth, he seems perfectly able to move himself around. No need for the damn narcan, which is a blessing, because Chuuya’s had to give Dazai narcan more times than he’d like in this lifetime.

Dazai pats the spot next to him again. Rolling his eyes, Chuuya acquiesces. Shoulder to shoulder, knee to knee; fifteen, twenty-two. They sit in quiet a moment, Dazai taking deep breaths Chuuya recognizes as an attempt to sober up. The summer breeze through the window adds a bit of warmth to the cold room. Nakajima is humming that tune again, loud enough to hear through a closed door. Chuuya closes his eyes.

“I escaped a little faster than I meant, but I got good information,” Dazai muses. When Chuuya glances over, an eyebrow raised, he waves his hand in dismissal. “Agency business.”

“Agency business,” Chuuya repeats flatly, “but you can send Nakajima here in the middle of it.” He’s indignant, even though an hour ago he said whoever drugged the two of them wasn’t his problem. It’s the principle of the matter — he can decide he doesn’t care. Dazai can’t decide that for him.

Yawning, Dazai scratches at his jaw. “I didn’t specifically send him here. I gave him your information a long time ago. You were closer than the Agency.” The drugs are making him a bit less playful, more direct than usual. His gaze is sort of lizard-like, unfocused on the wall opposite him. “Chuuya’s a good babysitter,” he repeats. Chuuya could vomit. He leans a bit away from Dazai, but Dazai just lifts one leg and settles it over Chuuya’s, holding him in contact.

They’re silent for a long moment, in which Nakajima begins to giggle, repeating Pingus to himself several times.

“What’re you doing with this kid?” Chuuya finally asks, glancing sidelong at Dazai.

There’s that Dazai smile. The actor one, the robot one, that reaches his eyes as though it’s clawing for them. “Does Chuuya have a soft spot?” he asks, leaning back into Chuuya’s space, chin hitting Chuuya’s shoulder. He whines when Chuuya plants a hand on his face and pushes him off. With the momentum he falls over himself so that he’s become a ball on Chuuya’s bed, moaning about how mean and awful and cruel Chuuya is.

“No,” Chuuya bites, “I just wanna know what you’re planning in your stupid mackerel brain.”

Said mackerel doesn’t respond for a while. Chuuya is reaching out to jostle him when he realizes the rise and fall of his back is real, actual sleep, and his hand stops in the air.

“Damn it,” he says, but it’s a quiet mutter. Out in the living room, Nakajima’s quieted, too.

He stands. Goes into the living room. Stares at the now-sleeping kid for a long moment. In sleep he’s serene, cheeks thin but still childlike, face still all smooth like an artist had just gone over the clay of him with her thumbs. Pingus curls under his chin. All sweet, except for the brown-red on Nakajima’s jaw, resting against Pingus’s dark fur.

Chuuya crosses into the kitchen, sits heavy in a chair, and considers. Considers — all of the safe houses Dazai could have sent Nakajima off to. Considers that stupid tune Nakajima and Dazai seem to love, and the edge to both their smiles, and the vigor with which Akutugawa and Nakajima hate each other. Considers how a man was dead, and how he probably deserved to die, but it had been a desperate, drugged eighteen year-old on a job who’d done it. Considers Chuuya’s a good babysitter, and tea with the Akutugawas, and Nakajima’s braces. He comes to no satisfactory conclusions.

Atushi please answer me if you had catnip would you get high I need to know this is very important information

First off, I'm a tiger, not a housecat, and I'm not sure if catnip works on tigers.

Second of, I have no idea because I've never eaten catnip or any sort of drugs, although one time dazai gave me a coffee so good that I'm pretty sure that's what drugs feel like, haha.

I remember i was asking kunikida why he liked coffee so much because honestly it's so bitter and dazai said he had some really good coffee that could definitely change my mind.

The next day he brought me some homemade coffee at work and it was really minty and i did NOT know coffee could be that good. i felt really hyper and i did even more work than kunikida that afternoon! He acted kinda weird about it though. He's not the competitive type at all so usually he's happy when i do a good job at work. Instead he was too busy because he took dazai to another room and kept shouting at him i couldn't tell you what it was about because at that point i was feeling kinda dizzy. Kunikida came back dragging dazai by the collar a little while later and I think i also saw yosano give dazai some cash when kunikida had let go of him. She looked pissed about it. Kunikida let me go home early when i told him i felt dizzy.

Even if though i did feel pretty light headed after, I still really wanna try that type of coffee again. but dazai said it was made from some super expensive foreign ingredient, at first i didn't really believe him and tried to search online for it, but i couldn't find anything about it and something that tastes that good and gives you that much energy must be hard to find so he's probably telling the truth!

headcanon that atsushi constantly has to try and ignore his cat instincts and constantly fails

atsushi, sitting down at his desk after a mission: it is SO HOT OUT. my throat is so dry, i think i’m going to die of thirst…

dazai, setting down a glass of water:

atsushi, looking at it:

atsushi, slowly using his hand to knock it off the desk:

dazai: ??? why did you do that

atsushi: i am SO THIRSTY

dazai, getting another glass of water:

atsushi:

atsushi, knocking it onto the ground:

dazai:

atsushi: i’m so thirsty

precanon dazai taking in an orphan but atsushi's a fully feral preteen like biting, growling, etc etc

touch starved atsushi who doesn't know how to ask for affection but has learned the following:

if he falls asleep on his desk near the end of his shift, kunikida will carry him back to his dorm (so now he pretends to fall asleep at least twice every week)

if he accidentally loses control of his ability, dazai will ruffle his hair to nullify it (so he starts controlling it enough to "accidentally" bring out random tiger features)

if he gets even a small bruise and yosano knows, she'll check it out and then pat his back after bandaging it (so he becomes more clumsy)

if he sits a little close to naomi during long boring meetings, she'll rest her head against his shoulder (so he makes sure to "accidentally" end up between her and juni or on her other side every time)

if he accidentally runs into president fukuzawa, the president will steady him by placing a hand on his shoulder (so he makes sure to almost bump into him at least once a week)

if he and kyouka are walking around in busy streets, kyouka will hold on to his wrist or hand or something to make sure that they dont go separated (so he gains an interest in all crowded shopping areas)

if he gives kenji a gift, kenji will thank him with a hug (kenji is very confused but pleased by his growing collection of random knick knacks given to him by atsushi)

if he says something funny, junichiro will chuckle and bump their shoulders (so he starts trying to be purposefully funny)

weirdly enough though... ranpo doesn't have a pattern but still he pops up awkwardly next to atsushi and bumps their shoulders or pats his back or something similar even though he isn't usually touchy... hmmm....

Headcanon that the reason why Atsushi’s eyes are purple and yellow is because the yellow part of his eyes is his ability. He was born with bad eyesight and couldn’t see shit so the tiger manifested itself in Atsushi’s eyes to fix his eyesight but now he’s also colorblind.

And then for Atsushi’s first month and a half of working at the agency every time Dazai makes direct skin to skin contact with Atsushi his vision gets 10x worse. And Atsushi’s too scared to point it out at first but eventually he’s like “hey guys every time Dazai touches me I can’t see and also I start seeing new colors what’s wrong with me”

Eventually they all figure it out and get Atsushi a pair of glasses so that he can turn off his ability every once and awhile, Atsushi also ends up learning how to drive because Kunikida and Yosano can’t just be the agency’s chauffeurs and even though he can only drive if he turns off his ability and puts on his glasses it’s still really funny to say that a colorblind teenager can drive better than 90 percent of the agency.

atsushi with more cat/tiger behaviors but some lesser discussed ones:

he scratches all the doorways of the agency building and his dorm. kunikida scolds him for damaging property for over an hour but while he apologizes he’s strangely uncontrite (at least for atsushi who tends to overapologize) about it

/

a mostly nocturnal sleep schedule feels the most natural to him but since his orphanage’s schedule was (quite literally) beaten into him, he regularly wakes up early, though after a long mission or multiple in a row, he tends to sleep through the day instead.

/

when really frustrated (usually during an argument with akutagawa) he has a tendency to stomp his feet. it tends to break the tension, and atsushi finds its super embarrassing. akutagawa finds it cute

/

he’s constantly fighting the urge to sit on his coworkers desks while they’re working and distract them. same with knocking things off their desks.

/

head bunting!!!! he first starts doing it to kyouka after the end of the guild plot. just does it to her one morning while they’re cooking breakfast without realizing. he’s mortified for a moment until kyouka does it back, equally shy yet earnest about it. slowly he catches himself doing it to the rest of the agency: when kenji gives him a hug after a mission, when yosano buys him something he was looking at during a shopping trip, while sharing lunch with the tanizakis, to ranpo after atsushi solves his first mystery on own, to kunikida and dazai after a dangerous mission. he hasn’t worked himself up to doing it to the president yet (and fukuzawas kind of sad about it). dazai and kunikida are the most flustered by it, kenji and kyouka do it back to him the most.

/

as much as he hates being locked up or confined against his will (and he really hates it), he genuinely loves being in small spaces. he sleeps in the closest for kyoukas privacy but he does geniunely feel comfortable there. sometimes he eats lunch under his desk or in the supply room if he’s feeling stressed. dazai did give him a giant box once to see if he’d sit in it and he totally did.

/

he tends to suck on the corners of blankets and things like his shirts or sweaters when he’s asleep or distracted. dazai used to tease him for it until he read that it was often found cats taken to soon from their mothers. he didn’t really find it funny after that

/

he will just Stare at people. agency members look up from their work and will see him looking directly at them. he usually snaps out of it right after and apologizes but just like slow blinks and winks and closing his eyes, he starts doing it more and more as he gets in tune with his ability.

Headcanon: Atsushi can only fall asleep when he’s either completely exhausted or when he knows he’s safe.

He rarely got a good nights sleep growing up. Something that carried over when he was abandoned to the streets. He’d walk for hours despite having no energy hoping it would tire him out enough.

The first true good night sleep Atsushi had was during a game night with the Agency. Dazai was in the middle of antagonising Kunikida when Atsushi slump forward.

Luckily he only lightly head butted Dazai’s shoulder.

But he didn’t move.

Dazai was going to ask what was up and then noticed Atsushi was knocked out. He got everyone’s attention and Ranpo deduced it was because Atsushi was exhausted.

Kunikida made a note to make sure Atsushi wasn’t overworking himself (hypocrite.) While Dazai attempted to gently pry Atsushi off him. He froze when Atsushi cried out and clung to Dazai’s arm. His whole body shaking with fear.

Ranpo’s grin left his face, he took off his glasses and simply gestured for Dazai to stay.

Dazai frowned but did so. Running a hand through Atsushi’s hair and reassuring him he was here. It was a relief to them all when Atsushi calmed down. Make an adorable chuffing sound as he did so.

Kunikida questioned what was happening and Kenji said he seen animals on the farm act like this. Ones that were injured or had been mistreated by others would act on edge.

But when they found others that made them feel better they’d act more like themselves.

And stick to the others like glue.

And the Agencies were Atsushi’s glue, his safety.

A blanket was wrapped around Atsushi and in the end they all had a sleepover in the living room of the dorm building.

Because after that none of them could bare to leave Atsushi alone right now. And Atsushi had the best sleep he’d had in years.