Disclaimer: Of course I don't own My Hero Academia, its characters, or the franchise.
Story: Izuku ends up enjoying a fan convention, only to surprisingly run into and befriend none other than Sir Nighteye. Not that she knows that. Mirai on the other hand finally found a kindred spirit, albeit someone young. These two end up traversing a friendship full of fanboyism and fangirlism, all the while tip toeing around the awkward 'other' tension between them, even when All Might himself enters the equation…
Set as an AU genderbending fic, canon-rewrite.
Spoilers: Probably the whole series, at least up to the Overhaul arc.
Warnings: Age disparity, underage, cursing and sexual situations…
Pairings: Fem!Izuku/Sasaki Mirai (Sir Nighteye)

A Fan's Guide to Heroics
Chapter Six: Overnight

Mirai carefully ate the katsudon he'd had delivered to him for lunch, typing up a thought with one hand, eyes periodically glancing at the TV screen he had playing the anime that he'd just been introduced to. Whatever Izuku had said to him, he'd taken to heart —he also admitted to some resemblance to the character she'd mentioned.

Ootori Kyoya held the same meticulous air and the physical aspects was ridiculously spot-on. His dark hair in disguise and the not-so neat (but neat enough) brushed hair (though he'd let his own hair be a tinge more messy), as well as the worn glasses, made Mirai too similar to the fictional character.

"Sir, I've got a call from the Best Jeanist Agency —" Mirio stepped into his office and paused, glancing at Mirai and then at the TV. "Sir, are you watching an anime?"

"Whaat?!" Awata suddenly appeared. "Sir isn't working, especially at work?"

Embarrassed but not wanting to show it, Mirai's glare became even more pronounced. He moved his glasses up. "For your information, I was told I resemble that character," he pointed out. "I just wanted to see what they meant."

Both of them tilted their heads.

"Hm, yeah I can see it," Awata said thoughtfully. If they'd seen him in his disguise, they would be a lot more agreeable. But he'd taken care not to expose them to it. "I think I know this anime. It's really old though," she continued. "Huh. Looks-wise, I can agree, I guess. But personality? His true Shadow King personality, sort of a little. But you definitely can't pull off his cool, charming host side."

For some reason, that offended Mirai. He could pull off charming if he wanted to. Izuku certainly thought he was charming…

Then again, she thought he was cute and his mind couldn't compute that.

Work was over soon enough and he rushed to the hospital he'd set Izuku up in, belatedly realizing he'd left behind the bag he'd packed up for the night. He ended up seeing Dr. Ishida first, after nearing her room.

"I just healed her arm, but it'll be sore. It's set up with a sling now and she's a bit disoriented, but she's okay to leave if you want to check her out," he informed him.

Mirai nodded and turned around as he went to do so first, and then followed Dr. Ishida into Izuku's room after he finished up. She gave him a lopsided smile when she saw him.

"H-hey, Sasaki-san. How was work?" she asked shakily while the doctor finished checking her over, and Mirai gave her a small smile, coming to her side and offering an arm when Dr. Ishida gave the okay. She was already dressed and ready to go.

"It was alright. Just the usual," he told her quietly, beginning to walk her out.

"Sounds e-exciting," she still beamed at him.

He tightened his hold on her and tucked her into his side more. Once in his car, he helped buckle her in and then was driving to her warehouse before anything more was said.

"I was advised it was best to keep watch over you until tomorrow morning. Are you…Are you okay with me sleeping over?" he tried to keep the nervousness out of his voice.

"Of course," she said sleepily. "There's no one I'd trust more with me."

He could feel his whole body become warm, a strange feeling coming over him and a fluttery sensation in his gut. If he was blushing too, he wasn't surprised.

In her loft, he settled her on one of the couches. Then he went to her kitchen and rummaged around to make tea and a light dinner for them. All the while, she watched him tiredly.

"Do you want a shower?" she asked quietly and Mirai froze in the middle of pouring tea.

"I-I forgot to bring some overnight clothes," he stammered.

"S'okay. You can borrow some of mine."

"Midoriya-kun, don't forget I'm a man," he emphasized, not really focused on the size difference but that there should be a wariness of a male staying over the night with her alone (that she was clearly not getting).

"I like Hero stuff, so I'll even buy clothing that are men's and won't fit me," she laughed and stood up. "Let's have dinner quickly and then I'll take you up."

Dinner ended up being a hazy memory because Mirai was too stuck on the fact that he was about to be naked and take a shower in Izuku's home…and then wear her clothing.

"So I have a couple boxers here that I haven't worn. My waist is too thin. Want the All Might 1st gen one? Guys wear boxers to sleep, right?"

"Y-yes," he answered, taking it and trying not to make too much fuss or act too nervous.

"I have some large shirts I'm pretty sure will fit you. I prefer large —comfier, you know? I may be small, but my chest makes wearing smaller shirts too tight sometimes."

He glanced once at her chest at that, before he dragged them away in mortification. He was horrified. What was wrong with him?

"Bathroom was back there," she said as she grabbed his hand. She led him out of her bedroom and brought him to the main part of the loft, towards the glazed out room he'd noticed before. "You can wash up here."

She left him to it and he hesitantly walked into the bathroom. He'd have to try to keep mostly clear of his hair so he didn't wash off the temporary dye. His contacts he'd take off for now, though he'd have to sleep with them after his shower…Stripping, he went into the modern shower and was startled by the multiple shower heads turning on and the light classical music playing in the background. He blinked.

Where did this girl get all this money from and why can't it help her out of situations like the one she was in?

Sighing to himself, he let the water run over him and though he was going to forgo the shampoo, he was still going to use her body wash. Her body wash. Was he…Was he going to smell like Izuku?

The twinge in his gut and twitch down there made him hunker down and place his face against his hands. Highly embarrassed and mortification rapidly retuning, Mirai took a few moments to reset himself. Then he quickly showered and toweled down, dressing speedily. He put his contacts back in and did a quick brush of his teeth with an extra toothbrush that was loaned to him. Then he went out and ran into Izuku, who'd been waiting for him.

She smiled lightly at him. "I thought I'd take you back to the bedroom? The way there was a bit long and you seemed lost in thought."

"I-I can sleep down there on one of the couches," he stammered. A couple of them could even fit his long frame fine.

She looked at him quizzically. "Of course not! I don't have any sleeper beds and I don't want you to be uncomfortable. You're a friend and guest, and my bed is more than big enough to fit both of us."

But it was inappropriate! And did she not even understand their age gap and that she was a young woman and he was a man? And…And…and he was attracted to her! He realized and finally admitted it to himself.

Mirai liked Izuku. She was cute, funny, sweet…She wasn't just pretty to him, she was beautiful.

How could he lay next to her and act like he wasn't affected? But then Izuku gripped his hand and was leading him away, and there was no way he could say anything more. When he was led back to the hallway that split off from the back of the 2nd floor, Izuku led him into it and opened the door at the end.

He stared. He hadn't noticed the first time…but geez. Her room was like another floor itself. Again open-plan, her bed was in the middle. The right side had a few racks of clothing and a couple dressers, while the left had an impressive line of display cases against the wall, with an arrangement of amazing Hero statues (he had a feeling they were her work).

She was right though. Her bed was huge, more than enough for his size even. It didn't change that they would be sleeping together in one bed.

She slipped under the covers once she'd let go of his hand. He hesitated before he climbed onto the bed and crawled to the spot next to her.

"You can get under the covers too, Mirai," she sleepily told him. "It can get cold when I don't put on the heater and I usually don't in the summer."

He hesitated again, but hearing his name from her lips made him happy and he didn't want to ruin it. So scooting up more, he grabbed the top edge of the duvet and the sheet and then slid underneath, already feeling her warmth. He sucked in a deep breath and held it when he felt her scoot a little closer.

"G'night," she murmured.

"…Goodnight."

The morning dawned nice and early and Mirai couldn't believe he'd manged to fall asleep, especially as well as he did. However, the fact that he'd woken up wrapped around her brought his anxiety back. And why did he have to have morning wood at a time like this?!

"Morning~" Izuku yawned, stretching in his arms.

He awkwardly cleared his throat and removed himself from her, sitting up slowly.

"Good morning," he replied to her uneasily.

She flopped onto her back and smiled up at him. "I haven't gone shopping for awhile. I'm pretty sure there's cereal though?"

"Cereal it is, then," he agreed and he got up first.

She followed after and they went out of the bedroom to the rest of the second floor.

"There's a dumbwaiter elevator there, when I need to transfer things from any of the floors to the others. Usually food," she laughed.

Mirai saw the dumbwaiter. "I could get us the cereal and you can stay here," he offered. Breakfast in bed…

"Next time," which implied they'd do this again. "I'd like to have breakfast with you in my kitchen."

Oh, this felt domestic.

"Favorite cereal?" she asked suddenly.

"Fruit Loops," he admitted.

"Ooh, someone's got a sweet tooth," Izuku teased and he lightly rolled his eyes.

"I also like my coffee with lots of sugar and creamer," he shrugged. "Just not first thing in the mornings."

"Then plain?"

"As black as most Villains' souls," he grumbled.

That made her laugh, which led to him smiling.

"I like Frosted Flakes," she revealed. "And tea rather than coffee."

They traded smiles again and he liked how they kept sharing new things about each other everyday. Still, it was funny and ironic how they both liked American cereal. At least he could blame Toshinori for that though.

He set up the tea and coffee while she set up their cereal. At the kitchen table, they sat next to each other, him to the left side and her at the head.

"Do you have work today?" Izuku asked.

"Yeah, uh yes, I mean," he corrected, feeling too casual and relaxed with her. "What…what about you? Do you have class?"

"Not today. I'll just stay here and do work," she said thoughtfully. "Maybe catch up on classwork I'd missed."

Which reminded him. "I have papers from your teacher I was supposed to give you. He gave them to me when I asked him if he knew where you were."

"Oh, is that how you found out I was in the clinic? Makes sense, since Togawa-sensei is one of the three of my emergency contacts. The other two are my mother and father, but my father is overseas and my mother travels a lot because of her job."

"Which brought in the next part I wanted to ask you. E-even though we basically just met…you could make me one of your emergency contacts." He tried to sound logical about it, which he could do most of the time. He just wasn't sure he could with her.

"Oh, yeah, I-I'd like that, if you don't mind," she blushed prettily. "Since my parents aren't usually around and I'm closer to you than Togawa-sensei."

"I don't mind at all," he continued hurriedly. "I'm arguably close by and I'm usually reachable. And it would ease my mind, especially if a situation like this happens again."

He'd hated feeling lost and worried, not knowing what happened to her. At least this way, he could be more informed and not be left in the dark.

"Thank you for helping me out so much and being there for me."

The stain on her cheeks was dark and her lips curved in a shy, sweet smile towards him. His heart pounded in his chest and it was like he was falling in love all over again.

Oh. He was in love.

Started 1/4/23 – Completed 1/6/23

A/n: Poor Mirai is just getting one epiphany after the other~ Welp, it'll just gonna make things incredibly fun to watch as he crashes and burns :D

Quick Points:

1. Timeline/Ages: In the future, I'll probably put up a timeline of things (since I've started work on one), but as for ages –yes, Mirai is currently 37. The story starts right before the series, so the 10-month training with All Might hasn't passed, hence Mirai will be 38 in the time that passes. Izuku is also canonically 14 at this time, but will turn 15 in a few months from the time the two currently are at, which is actually really close to when Izuku meets All Might (in the month of April). Also mean she'll be 15 before he's 38, and then as the story progresses, she'll probably be around 16 at the time "Heroes Rising" movie events. Hope that clears things up better!