The first time you used your quirk with Midoriya was after All Might’s class where he had had to battle Katsuki as if they were hero and villain. Recovery Girl hadn’t been able to use her quirk in fear of exhausting Midoriya too much, but you refused to watch him suffer.
You talked with her and convinced her to let you help. Grabbing Midoriya’s hand, you started to see his broken arm return to a normal color and the burn on the other one disappear. In exchange, your right arm now was dark purple and your left one had a painful, bright red bruise.
You didn’t mind at all: Midoriya using his quirk had been Katsuki’s fault and he shouldn’t pay the consequences. Also, compared to the cramps you got before starting the HRT, this pain was nothing you couldn’t bear.
You heard Midoriya start to wake up, visibly confused.
“Hey, everything alright?”
“Yeah, a little bit sore… no, wait, actually… actually nothing hurts? And I’m not even too tired. Recovery Girl did an amazing work as always.”
The old woman kept typing away on her computer, not even stopping to answer the kid.
“It wasn’t me this time, dear.”
Midoriya was growing more confused with each passing minute, when he saw your right hand all purple and a bit swollen. He looked at his own arms. Not even a scratch.
“(Y/N)! You- why- you shouldn’t have- thanks but-“
“Dude, chill. Breathe.”
The boy took a deep breath, eventually calming down.
“Are you okay? Does it hurt?”
“I’m fine, Midoriya, don’t worry. By tomorrow they will have disappeared. It hurts a bit, but it’s nothing I swear.”
He sat up and hugged you. When he let go he was smiling at you as if you were his guardian angel and that smile did things to you that you were too embarrassed to think about. You grabbed his hand and smiled back, your smile growing bigger when he started blushing and stuttering.
That afternoon he ended up walking you home, carrying your backpack for you and taking notes about you on his notebook. For the first time, you thought that your quirk gave you a whole lot more than just pain.
The days went by, Midoriya and you growing closer.
“Say, (Y/N), why do you never change into your suit with the rest of us?”
“I’d rather not-“
“Is it because you’ve got scars? We all have scars-“
“No, Izuku, it's not because I have scars.”
“Then why? I thought you got along with the rest of guys in class.”
“Deku, I’m trans.” He was quiet for a while, he had his typical I’m-thinking-so-hard-but-I-don’t-know face on. “It means when I was born the doctor told my parents I was a girl, but they ended up being wrong.”
“Oooh so like Tsuyu but the other way around.”
“Yeah, she told me a while ago when I asked about some pills she was taking. Told me they were estrosomething.”
“Yeah, that, and that she had to take them because her body didn’t make them itself.”
You were at a loss of words. He was clearly a bit uninformed, but he was completely and absolutely fine with it.
“So will you come with us from now on?”
“Dude, so what if your body is a bit different? Have you seen some of the guys’ quirks? One has multiple arms, another has a tail, Katsuki has that face…” At that you couldn’t help but burst out laughing. “Seriously now, (Y/N), you are a great guy and everyone in class likes you. And if someone dares say something…” He stopped grabbed your hands and grinned up at you. “I’ll be there to protect you.”