Chapter Text
"Did you know," Mori starts as he traces the edge of Dazai's soulmark with a scalpel, "that there is such a thing as an artificial soul binding?"
Dazai doesn't say a word, staring at Mori with a careful blankness that doesn't suit his young features. Mori doesn't seem to mind the lack of response, continuing on without waiting.
"It's not a very well known procedure–for good reason, of course. Rogue soulbonds formed outside the will of the gods?" His voice adopts a faux horror, "The idea alone is revolting. Wouldn't you agree, Osamu?"
Dazai stares at him for a beat longer.
"What do you want, Mori?" He asks, and Mori's feigned disapproval turns into a smile just a little too sharp to be fond.
"Nothing you care much about," He says pleasantly.
Neither of them speak for the rest of the evening, Dazai never making a sound even as Mori slowly slides his scalpel under his skin, cutting away at the brilliant reds of his soulmark piece by piece.
----
No matter how many times Mori cuts it off, the mark always comes back, colors burning stubbornly brighter.
----
The night Dazai meets Chuuya for the first time, Mori spends hours patiently inking a sprawling tattoo across his chest and neck.
It's a cage, intricate cast iron bars weaving their way around the wings of the bird that had sprung to life the moment Chuuya's first kick had cracked his rib.
The chain at the top winds across his collar bones and around his neck, looping around like an ill-fit metal scarf, ready to be taken up by Mori at any moment and used to drag him away.
"It's almost finished," Mori had said softly as Dazai lay there, limp on the table.
Dazai knows he wasn't referring to the tattoo.
----
If Chuuya knows they're soulmates, he doesn't say. Maybe he does know but doesn't want to admit it.
Dazai can't exactly blame him, he's never been interested in having a soulmate and even less interested in being someone else's. Soulmates drew pain like moths to a flame, and Dazai had had enough of that for this lifetime.
----
Mori doesn't say a word about his soulmark for years after that.
Maybe he lost interest as soon as Dazai started looking less like a child. Maybe he was biding his time. It didn't matter either way, Dazai wasn't planning on being alive to see the fruits of the doctor's labor.
Then he turns eighteen.
He still wants to die, of course he does, but as he drinks with Ango and Oda, as he tries curry and listens to the happy screaming of orphans as Oda visits, Dazai considers–just for a moment–if it wouldn't be alright to die a little later than he'd planned.
"Odasaku?" Dazai pokes at the sphere of ice in his drink, "Do you have a soulmate?"
Oda hums, before quietly responding.
"Not anymore."
Ango grimaces in the corner of his vision, but Dazai just gives Oda a small smile.
"That must be nice."
----
"It's been too long, Osamu," Mori says after Dazai reports on the updates for their newest enemy, Mimic, "Come to my room tonight."
Dazai hums his acknowledgement, and the wings of his mark beat furiously against their inked cage.
Chuuya gives him a strange look when he leaves the office, opening his mouth and for a moment Dazai thinks he's finally going to ask, finally going to voice the concerns Dazai knows he has, but then his mouth shuts and Chuuya just frowns.
"Look," Chuuya bites out, "I don't know what the fuck is up with you right now, but you better sort it out before I'm back from the west or I'm kicking your ass. You're annoying enough when you're in a good mood."
"Chuuya shouldn't worry so much," Dazai says, reaching out to poke right between the red head's furrowed brows, "It will give him even more wrinkles."
"I don't have fucking wrinkles you piece of shit–"
Dazai laughs as Chuuya scowls, and all is forgotten.
----
It's the last time he sees his soulmate for 4 years.
----
"Aren't I a little old for you?" Dazai says when Mori starts pulling off his clothes with meticulous practice.
The man laughs, pushing the white button up off his shoulders and revealing the caged soulmark.
"Maybe," He admits with a smile, "And yet here I am, wanting to touch you again. I think that says more about you than me, Osamu. Even with my tastes, I have to admit you were made for this."
Dazai huffs, "To be fucked?"
"Nothing so crude," Mori chastises, "It's more than that."
He takes Dazai's jaw in his hand, dipping down to brush their lips together in a kiss gentle enough to make him wonder for a flickering moment if Mori really does feel something more for him.
"Can't you feel it? Why do you think you've felt so empty all your life?" Mori asks, "You were made to be owned, Osamu, and without it…" He sighs, "It's hurt me to let you live like this for all these years, but I won't let it go on for a moment more. After tonight, you will be complete."
Mori doesn't give Dazai a chance to figure out what that means before he's kissing him again, leading him back and laying him out on the bed.
Dazai hardly feels a thing as Mori holds him down and carves out the soulmark once again, cuts deeper and more vicious this time than they've ever been before, but unlike the past he doesn't peel away the layer of skin just yet. Instead he takes his blood stained fingers and opens Dazai up, fucking him the way he used to when Dazai was half his size and too young to understand just what he was giving up.
He fucks him slowly, working him over in a way that proves how well Mori knows his body, and when Dazai starts to twitch, toes curling and fingers aching to grip onto the duvet, Mori wraps one hand around his cock and the other digging under the cut skin of his chest and pulls.
The mark is ripped off his chest just as the orgasm hits, and Dazai's brain shorts.
He hardly gets the chance to feel the way the inked lines of his cage tattoo burn before his world slips to black.
----
He doesn't even realize what Mori's done to him until he's already run from the Mafia with Odasaku's voice echoing in his ears.
There's a heartbeat in his chest that isn't his along with a rush of sick satisfaction he can't outrun no matter how far he gets from the mafia HQ.
"Did you know that there is such a thing as an artificial soul binding?"
Dazai feels a distant laugh start to build in his chest, right where his soulmark used to be. The bird always came back. No matter how many times Mori cut it off it always came back. Why isn't it coming back?
He laughs, and laughs, and laughs until his voice gives out.
Did you consider this, Odasaku? He thinks bitterly, Did you know what you were really asking of me?
----
"What about you, Dazai-san?" Atsushi asks innocently, "Have you met your soulmate?"
"Don't bother," Kunikida huffs, "Dazai refuses to say a word about it. Not that I want to know what kind of woman is stuck being soulmates with him."
"Don't listen to him, Atsushi-kun," Dazai chirps, "He's just jealous because his soulmate is–"
Kunikida launches himself at Dazai before the man can finish the sentence, a flurry of disapproval and anger coming out of his mouth as Dazai cackles.
Atsushi watches with a sheepish smile, feeling far more fond than he should be for people he only met a few days ago.