Dazai and Atsushi are best friends (soulmate if one were to ask how they felt about each other) since their eyes met. The breathless laughter of surprise warm happiness, the silly growls of hungry stomachs and the instant safety they never had once their names graced the empty air. They are best friends and would end the world for the other if it means keeping the other from harm. Dazai has proved this when he let himself get caught by the Port Mafia and beaten by someone he doesn’t care for. Atsushi proved this when they jumped off a flying whale, knowing Dazai is at the bottom waiting for him.
Best friends.
That’s why they have sleepovers every two days. (It would have been everyday but both fear the idea of co-dependency and actually having someone in their life. Almost as if having the person everyday was a dream that could be torn at any moment.) Why? Because it surprisingly helps them sleep better. So on the days of their sleepover, they would ditch work early (Dazai will do all his work, by himself the afternoon before to the lunch the next day. Cause a lot of strokes.) to run errands. Picking up groceries, snatching the latest horror films that Atsushi had been wanting to watch and Dazai was dreading.
The tiger vessel found it hilarious that the Ex-Mafia Executive hated scary movies.
Anyway! After they were done, they would head home and it doesn’t matter who’s home. (Atsushi, unsurprisingly, is the only one who has the knowledge of where Dazai truly lives.) So once at home, the dark brown hair man would play soft sound music with only instruments or opera music from different countries. (Carmen was Dazai’s favorite because he found the whole story hilarious while Atsushi found it annoying and stupid. Lion King was an agreeable favorite though.) The silver hair young adult would take out the pans and ingredients they needed.
It somehow became easy to cook with each other, more than they thought. Dazai would cut the vegetables, the meat or fish and toss it into pan. Atsushi to stir, fry and mix. Making a meal together made them feel human. Like they weren’t trapped in a clay golem created to hold them prisoner. Once everything goes quiet, Dazai will sometimes gaze into the air with empty eyes and softly tell his best friend the horrible shit he has done in the past. Especially what he did in the Port Mafia. Atsushi will listen with an open mind, knowing that one miss-step will cause the other to clamp up.
(He would always turn the stove off at these moments. These nights always took his full attention. Causing her to take deep even breathes to stop her shaking, to keep from spiraling at the thought of her person being like that blasted Headmaster. To try to process and work through the disgust he felt. They would slowly turn to their Osamu and ask in a soft tone if they could hug him. Never once did the idea of blackmail or punishment cross her mind. This would cause the rusted brown eyed male to break and talk about how truly empty he felt with his treatment of Akutagawa. Dazai would always be completely grateful for this and will cling to his tiger.)
In the same way, Atsushi will do the same. Talking about the orphanage and his treatment as if he was there in third person. (This too was never used as blackmail or a way to hurt the younger. In Dazai’s dark, fucked up mind this was the line no one cross.) Of course this led to conversation that neither could talk about. Like the last words of the dying Odasaku or the pain of brutal human experimentation or the hatred Book. Then when it was time to sleep, they will curl up (depending how they were filling that day, they would switch on who was the little spoon) and whisper their deepest, darkest wish they desperately beg would happen. Then they would fall into a comfortable silence as they listen to each other’s heart.
Then agency, mostly Yosano and Kunikida (both having their own sets of problems), don’t really understand why or how this became a tradition.
But Ranpo does.
He always knows.
He knows in the way how they stress on certain jobs then relax once they see the other’s figure. How they smile once they could hear the other’s voice. Could see how they pull each other from the past and enjoy the present. He could see how love and touch-starve these fools are desperately in need of a judgmental free zone. So quietly as he can, Ranpo helps in anyway he can. From babysitting Kyoka to running interference after life n’ death situation.
After all, he was the world’s greatest detective and knows that if one was gone then the other will follow. They were soulmates after all.