eye hair = transforming to wild cat

Shin Soukoku HCs

I really enjoyed writing the original Soukoku headcanons here so I felt like writing some for the Shin Soukoku!

As usual, for @dazaiscans and of course for @hyakuraii.

Mild spoilers for those who haven’t caught up to the BSD manga - although if you know about the “shin soukoku”, then you should be fine. A lot of these are simply my own headcanons though!

REALLY LONG POST BELOW ASDGHSJKL


  • When they first began working together, Dazai had suggested that they needed to “understand each other first”. Although this started off with someone trying to kill the other person, and that other person just trying to stay alive as long as he can. Wait, did I mention they’d probably be forced to live together? Dazai’s idea. Atsushi protested the most at first (“What if he tries to kill me in my sleep?!”) and Akutagawa was pondering whether to simply capture him for the Port Mafia or to actually leave him alone. But hey, it worked out in the end. Awkward roommates, everyone’s had that, right? They have to share the laptop, though.
  • Somehow Akutagawa and Atsushi still bonded over the fact that they both grew up relying on no one but themselves, and having “parental” figures (Dazai and the orphanage headmaster) who, despite treating them roughly and violently, still fed and clothed them, taught them how to read and write, made them stronger through suffering.
  • Learning more about each other was - is probably still - kind of a touchy business for both of them. It seemed awkward to know about the likes and dislikes of your ex-enemy, even though now it was more of a “you’re my rival so it’d be meaningless if you died so get yourself together you bastard” kind of thing. So most of their rare talks are usually punctuated by long pauses and the occasional “oh”s.


  • As incompatible as they are outside of battle, once they fight (Soukoku vs Shin Soukoku practice matches?? Anyone????) they just click. There’s still yelling at each other every once in a while, but they just trust each other somehow, covering for each other’s mistakes and blind spots, making the most out of Rashomon’s destructive and freeform potential combined with Atsushi’s athletic close-range combat.
  • P O S T   B A T T L E   F I S T B U M P S ???
  • IDK THEY’RE BOTH WORN OUT AND DAZAI DECIDES TO GIVE THEM A BREAK AND CALLS IT A DAY, AND OUT OF NOWHERE ATSUSHI JUST RAISES A FIST TOWARDS AKUTAGAWA AND OUT OF FUCKIN NOWHERE AKUTAGAWA FISTBUMPS BACK????????
  • Like they have no idea how it even started. It was an accident, and they just stuck with it.
  • Post-battle treats! Atsushi is the kind of guy who believes in treating himself after a job well done and Akutagawa has nothing else to do so he just tags along, and witnesses the strangeness that is an eighteen-year-old getting excited about ice cream trucks (me too tho) and having cake while Akutagawa awkwardly sits nearby with his tea.
  • Oh yeah, Akutagawa’s very particular about his tea. Once Atsushi accidentally laughed out loud at Akutagawa’s expression from the waitress messing up his tea, and was treated to a brisk lecture about the deep culture and history behind tea that deserves the utmost respect.


Okay while Dazai and Chuuya know loads about each other, like different languages and instruments they can play and places they’d like to visit, Atsushi and Akutagawa are still in that process of learning how to be comfortable in the same room as one another for more than ten minutes.

Still, it’s a nice change for both of them to see what it’s like when one isn’t trying to not be a nuisance and the other isn’t out killing other people.


  • For starters, Atsushi learns that Akutagawa likes antique calligraphy. Not just writing, either, he paints really well. Cloudy mountains and cherry blossom trees and crashing rivers, in colours that Atsushi didn’t even think existed in Akutagawa’s life - he’d assumed everything was either black, white, or red as blood.
  • What if Akutagawa hums when he’s happy? Not full-on singing or any popular songs or tunes, just humming short melodies that don’t really mean anything. This is usually when he’s reading.
  • Rashomon usually takes the form of a wolf to attack (I’ve always thought it resembled the Wolf counterpart of Kindred from League of Legends), but one day Atsushi finds out that when Akutagawa isn’t really paying attention, his coat automatically takes form anyway - as a cat.
  • Yeah, a cat. It doesn’t do much, just padding around and sleeping next to Akutagawa as if it’s an entity on its own. Atsushi doesn’t try to question it - he accidentally stepped on the cat’s tail once and it bounced up, fur on end, and Akutagawa gave him the strangest look. Almost like “seriously?”
  • Inside Atsushi’s head: IT’S A CAT I WANT TO PET IT? BUT IT’S NOT A REAL CAT? IDK IT PURRS? BUT IT CAN KILL ME?


I’m thinking of more cute stuff for shin soukoku while soukoku is a lot of angsty shit wtf


  • Atsushi’s the worrier among the two of them, he looks out for Akutagawa especially when his coughing worsens, and he can’t help asking if he’s okay and maybe offering to make his tea for him.
  • Ok but imagine during one winter Akutagawa’s coughing gets even worse and Atsushi realises he’s actually sick, he’s got a cold and a red runny nose and everything, but being full of pride Akutagawa doesn’t say anything about it, just uses Rashomon to warm himself up - and Atsushi buys him (OR MAKES HIM ONE? shin soukoku writers I’m looking at you now) a scarf to keep him warm and. Akutagawa just mumbles “thank you” and keeps it on.
  • Akutagawa’s ability Rashomon is “the ability to control clothing” (translations of Ch24.5 from Akutagawa’s backstory, if I’m interpreting this wrong then this headcanon goes to shit), so while Akutagawa’s black coat is the carnivorous beast that devours everything, the scarf (white-grey, like Atsushi’s hair, or more like the fur of the tiger he transforms into) that Atsushi gave him turns into wild flowers, or sometimes the cat that Atsushi is torn about wanting to pet, but Akutagawa never uses the scarf to attack. Ever.


  • Atsushi’s a restless sleeper and it pisses Akutagawa off. He thinks about putting the man-tiger in a straitjacket to stop him from kicking stuff around the room.
  • Akutagawa’s one of those people who takes a long time to fall asleep, but wakes up at the slightest noise by simply opening their eyes. No yawning, no stretching. It’s kind of terrifying.

  • Video games?? Atsushi’s more of a casual gamer, occasionally plays Minecraft and probably has Neko Atsume on his phone. Akutagawa’s scarily good at games like Dishonored.


Yeah these headcanons are definitely more like roommate headcanons. Oh well.


  • Birthday shenanigans. Neither of them are the type to throw birthday parties, and don’t expect much from others.
  • But Atsushi definitely gets an over-the-top birthday party from the guys at the Detective Agency, with presents from everyone. Fast forward to when Atsushi goes home, and there’s a little grey kitten in his apartment. He should really be wondering how it got here, but he’s too busy cooing over it and petting it and spoiling it, until Akutagawa comes back too and he just doesn’t bat an eye, just gives Atsushi (and the cat) a brisk nod and goes back to his corner of the room to read. What a surprise.
  • No one in the Port Mafia cares about things like birthdays, except maybe Elise who makes an effort to remember the birthdays of people she likes. Higuchi doesn’t know when Akutagawa’s birthday is, and part of her knows that she’d probably get slapped again if she dared to ask. Gin simply acknowledges her older brother’s birthday with expensive tea (illegally obtained) for him, and Atsushi gives him like. A new coat, maybe a new book. Actual presents.
  • Needless to say, their relationship improved after that. Akutagawa stopped calling Atsushi “man-tiger” and started calling him by his last name “Nakajima” instead.