This is short, but I've been having a VERY shitty time, and this is me going 'hey still breathing'. Hope you all enjoy anyway.
There's a single moment, before adrenaline dumps into your system.
A single moment before your heartbeat kicks into overdrive, and flight or fight kicks in. A moment before thousands of years of instinct and evolution goes into effect.
Todoroki Touya knew adrenaline intimately. He'd known it since he was little, since he'd stood between his siblings, and his father. Since he staged his 'death' and ran. Since he'd stepped into life without a steady roof and food, where he lived on the street and everything depended on his mind.
He'd sworn to himself that he wouldn't let himself get so attached to anyone ever again. Leaving Fuyumi, Natsuo, and Shouto behind...he couldn't make a choice like that again. His best option was to be a loner.
He hadn't counted on Midoriya Izuku. The younger boy was a force to be reckoned with, determined and stubborn enough for five grown men. He reminded Dabi of his siblings. And maybe it was the reminder, maybe it was just the suppressed big brother instinct, maybe it was the protector he's always been, before…
Whatever it was, he couldn't ignore the kid, with his nose in places it didn't belong, who bit more off then he could chew. He had fire in his eyes and a stubborn streak a mile wide.
Dabi broke his own rule- he stepped in. He stepped in, and he saved the kid from his own stupidity, stepped in and made sure he got out of it.
Then he tried to leave, to separate himself from the boy, after making sure he wouldn't bleed out. He justified it as 'not wasting my time by saving you and then letting you bleed out and die' but really...he reminded him of his siblings.
His mistake was thinking that Midoriya Izuku would let him walk away.
Which was how he got attached. Because Izuku was a stubborn, focused, driven and charismatic little shit who Dabi was kinda pissed he liked. Because he was also a goddamned trouble magnet. If he didn't know the kid was quirkless, he'd swear that was his quirk- even over his brain.
Todoroki "Dabi" Touya knew what adrenaline felt like, what it did, intimately. People talked about how it let you do amazing things, how it made everything slow down, and made you react quicker.
But adrenaline wasn't some super-quirk answer to the world. It wasn't there to make you think. It was there to help you fight or flee. It was made to help instinct along- not to help you solve problems.
Adrenaline made you stupid, instinctive and unthinking.
Dabi knew that. He knew it- it was what had earned him his scars.
But watching this League of Villains 'Sensei' take interest in Izuku, watching him try to take Izuku to make him a Nomu…
Dabi's first instinct is fight. In the split second between the adrenaline dump and thousands of years of instinct, Dabi's choice is to burn the bar, and everyone in it, to the ground- so long as he and Izuku can walk out.
He'd lost one little brother already- he'd burn the world to ash before he gave up another.