Chapter Text
1. Medical Knowledge
After finding out Dazai is far more skilled than he led them to believe - which was already surprising enough, given how Dazai was already maybe one of their most skilled members barring Kunikida - the Armed Detective Agency were determined to find out what else their mysterious colleague had up his sleeve. They knew better than to try and go behind his back to find out, since he always figured them out early on, so they just outright told him they would be observing him extra closely for a while so he doesn't freak out or something. Dazai, still exhausted from the week he'd spent with Nakahara, only arched an eyebrow but otherwise let them be.
It wasn't like he was actively hiding his skills. It just never came up.
For instance, no one ever asked why he so rarely went to Yosano for treatment despite seeing him get tossed around or manhandled by the latest enemy. Yosano had even only found out about his knife wound from the Dead Apple incident by accident. He'd been teasing Kunikida, as usual, when the blond had grabbed him and started shaking him, also as usual, only Dazai's stitches hadn't even settled yet before he was being jostled so of course they reopened and blood seeped through his clothes. (An unfortunate side-effect of no longer wearing black.) Yosano scolded them both then outright gushed at the clean stitches she found when she dragged him into the infirmary. She hadn't even asked, so of course Dazai didn't say anything.
After the incident at the firing range, though, and with everyone studying every move Dazai makes, it was inevitable they'd one day watch him get injured on a mission.
It was another knife wound. Dazai had taken it to protect some kidnapped boy they'd been tasked with finding and rescuing from his psycho, Ability user girlfriend. The knife had nothing to do with her Ability, she could actually control electricity or something, but she'd gotten desperate when she realized she was no match for the Agency and so she'd tried to kill her boyfriend in a 'if I can't have him, no one can' move. Dazai had seen the move from a mile away and had bolted forward, just barely throwing himself in the way. Kunikida and Kyouka, his partners for the mission, called out his name in worry, but Dazai already had the knife wrenched out of the girl's hands and was applying pressure to a specific bundle of nerves and muscles at the base of her neck that caused her to go limp. She wasn't unconscious, but Dazai dealt with that a second later.
As a seasoned (ex) mafioso, he always carried a handkerchief and some chloroform on him in case he needed to gently knock someone out. With the girl no longer being a danger to them, Dazai first turned to check over the victim, even as Kunikida tried to fuss over his wound.
The brunet just waved him off. "This is basically just a scratch, relax, Kunikida-kun. I've fought entire enemy organizations with far worse."
"That's not helping, Dazai!" But anything else Kunikida could have yelled at him was shushed by the brunet.
"He seems to have a concussion; you yelling won't help him. Now shut up and make me a small flashlight."
"Here, I have one," Kyouka offered, handing him the light. He thanked her before expertly moving it from one eye to the other, asking the teen questions as he determined his level of awareness and how he responded to stimuli.
"It seems that she didn't hit him hard enough when knocking him out to crack his skull, thankfully," Dazai commented as he pressed around at the back of the boy's head, shushing him gently each time he whimpered from the pain. "He will need stitches, though. Probably no more than three. His metacarpals on his right hand also seem broken, but I don't feel confident enough to bind them with anything we have here, it might just hinder further procedures. Also it seems his right radius is fractured. He's suffering from malnutrition and bordering on an overdose of sleeping pills besides. He'll need to go to the hospital for that, especially with the concussion in the mix. Other than that, I think he should be fine. He doesn't seem to have any broken ribs, which would have really made things bad in regards to moving him without a stretcher. Stitching him up in this lighting, however, is a no go. We should just bring him back to the Agency or straight to a hospital-"
The boy latched onto Dazai with a frenzied, terrified look on his face at the prospect of being separated from Dazai at the moment.
The genius changed his statement immediately. "Agency it is, then. Then when his parents come, they can decide where they want to go after their reunion. That okay?" The boy nodded and immediately regretted it with the concussion messing him up. "Right. Kunikida-kun, you get the girl. Kyouka-chan-"
"I've already contacted the police."
And so, they dragged the two teenagers - around sixteen years old, the both of them - back to the Agency where the boy finally let go of Dazai in order to fling himself into his parents' arms even as Yosano dragged them all into her infirmary. The authorities came to pick up the girlfriend and asked some questions regarding their report but Kunikida attended to that, leaving Dazai more or less to his own devices.
He was just lucky his knife wound was in a place he can easily reach so he didn't need much help when he just cut up the area around it on his pants at his thigh and immediately started cleaning the wound. A short inspection told him it wasn't too deep but stitches would still be recommended for proper recovery, so he got down to that with the mini first aid kit he stored in his coat. He was well aware of the eyes on him as he swiftly and efficiently pulled the thread through the meat of his thigh, not once wincing in pain. His tolerance was much too high for something as silly as this to affect him greatly.
"Knowing how to stitch wounds might be vital in this line of business, Atsushi-kun," he told his protege, who jumped in surprise at being so suddenly addressed. "Yosano-sensei won't always be readily available, after all. Knowing how to keep yourself alive until she gets there is important. Though, I suppose that's not much of an issue for you, but the skill would still be of use to your comrades."
"Dazai-san was able to give a detailed diagnosis, though," Kyouka said pointedly, asking without asking, and Dazai decided to oblige.
"Before Mori-san managed to become the Boss of the Port Mafia, we stayed a few weeks in his old underground clinic. Sometimes it would get so overcrowded with patients that he needed assistance. I learned fast, so he continued teaching me. Most of my medical knowledge was later transferred to torture and interrogation lessons, as well as taking care of Chuuya post-Corruption. I know how to treat just about any battle injury with just about any resources at hand, but if someone is near death, I'm not skilled enough to keep them alive for long. I can, however, identify over 50 different poisons, 17 types of overdoses and at least 27 ways of traceless murders without a laboratory examination. I'm also unfairly well trained to use most medical tools. Scalpels are basically extensions of my fingers at this point and I can stitch a wound close in under a minute in pitch black darkness."
"Maybe we should team up and teach everyone at least basic battlefield first aid, Dazai," Yosano commented as she left the infirmary often doubling as her office, checking over Dazai's work and humming in satisfaction. "The kid should be alright. I used my Ability on him and he's going to the hospital for the concussion and the sleeping pills neigh on overdose. Good work out there, the three of you, especially you, Dazai. I had no idea I had a fellow medic?"
"If you know how to take someone apart, technically, you know how to put them back together," was all he said and they shared a grim look.
After that, no one was really surprised when Dazai did first aid on a battlefield before Yosano could get there to heal them. Dazai kept them from crossing over the threshold of death and Yosano yanked them back from it.
They made a pretty good team in that manner.