Swan dive (BNHA)

A hero's secret

Izuku and Rei sat on their sofa, watching the TV. They were watching footage of the fight between All Might and All For One, for what was probably the hundredth time.

Toru pushed the front door open and looked over at them. She had just finished school. Rei had been let off of her training for a few days to let the news of All Might's retirement settle in.

Izuku watched the footage with a apolitical eye. All Might's quirk. What was it? For the last few years, All Might had only worked for three hours a day and this had been getting even shorter, suggesting his quirk was weakening, but that's not how quirks worked. A quirk that got weaker over time, what sort of quirk could that be?

He still remembered that day on the rooftop, when he met All Might for the first, and last, time in his life. His injury could have kick started the weakening but it had been constant for five years, why would it suddenly get weaker again?

"Hey, Izuku? Were you listening to me?"

Izuku looked over at Toru. "Huh?"

Toru sighed. "I said that Iida, Yoayorozu, Todoroki and Kirishima wang to come over tomorrow. They want to be able to thank you properly for helping them save Bakugou, despite your relationship with him."

Izuku nodded, starting to drift off again into thought. The time he started weakening again was soon after he started teaching at UA but he was still teaching there, so he must be aware of what is weakening him  or he would have stopped it or left, to work on ad the number one hero.

Why had he started teaching at UA in the first place? Surely a hero of his strength would be better doing hero work, not to mention his time limit would barely cover his classes, so he had a very good reason for going there.

Was there any students that might be important to him? Someone he would want to look over.

Mirio.

His quirk was permiation but during the sports festival he had used something else. Something that looked suspiciously like a strength enhancement quirk. Like All Might's quirk.

Could quirks be passed on? Is that possible? It was possible that there was a quirk that could be passed on from person to person. Izuku was literally a ghost, Rei had tentacles and Toru was invisible, things that were once impossible. So why couldn't a quirk be passed on? How crazy could it be?

"Hey, Rei. I'm going to call Mirio."

"Huh?" Rei ripped her eyes away from the TV "Why?"

Izuku dug his phone out of his pocket and scrolled through to Mirio and called him. "I have a theory that I want to test out."

Mirio picked up and his voice seemed as happy as it always was. "Hey, Izuku. What is it?"

Izuku took a deep breath. "You have a second quirk, don't you? One you got from All Might."

Mirio's voice wavered. "What are you talking about? Quirks can't be passed on, that doesn't make sense."

"Mirio, I'm a ghost. Try and tell me that that makes sense."

Mirio paused then sighed. "Fair enough, are you home?" Izuku told him he was. "I'll be there in five minutes."

***

There was a knock on the door and Izuku ran to open it.

"Is it Mirio?" Rei yelled from the kitchen. She and Toru were attempting to cook something, preferably without getting food poisoning.

Izuku opened the window and looked through the gap, seeing Mirio stood there, looking nervous. "Yep!" He yelled to Rei, opening the door fully.

Mirio wasn't surprised when he saw Izuku. When they had met, Izuku had been disguised as Izumi Midori, but he had explained it to Mirio already, saying he knew someone at UA who he wanted to avoid and that Rei had forced him into it.

Mirio stepped inside and peered around. Izuku pointed him to the lounge and ran to get him a drink.

Toru gasped when she saw him. "You're that third year who stripped and beat up the whole class!"

"Wait, what?" Rei walked into the room, holding a bowl of ice cream. She had given up cooking. It had turned black anyway. "I need to hear this story."

"Oh, I'm Toru Hagakure, by the way. Rei's my sister."

A strangely finger shaped hole appeared in Rei's ice cream and some was scooped out. "Toru! Get your own ice cream! And stop eating it with your fingers!"

Toru groaned. "Fine, mum. Do you want any, Mirio?"

"You can have any, but not the honey comb. That is mine and I will kill anyone who lays a finger on it." Rei threatened.

"She's not joking either." Izuku said, carrying Mirio's drink. "She once broke Toru's finger over her ice cream. It was difficult to explain it to Recovery girl."

Mirio took his drink and looked around at the three of them, then back at Izuku. "We need to talk about what you said on the phone. How did you figure it out?"

Izuku stiffened then sat down next to Mirio, gazing sadly at the floor. "For the last five years, All Might has only fought for three hours a day, due to his injury. However, this slowly decreased again after he joined UA. I remembered how you seemed to be unusually strong during the sports festival and put 2 and 2 together."

Mirio sipped his drink and nodded at Izuku. "But how do you know about his injury?"

Izuku stiffened and clenched his fists, memories of his last day passing through his mind. "I met him once. I caught him at the wrong time and saw him transform. He gave me a quick explanation."

Izuku felt the need to cry, but he knew it was useless. He couldn't cry anymore.

"That was right before I died."

At the mention of his death, Rei paled and walked over to him, holding her hand out to him. He smiled gratefully and took it.

"Oh. You should probably talk to All Might, so he knows that you know his secret."

Izuku nodded. "Yeah, if he could sort that out, that would be great."

The group fell into silence again but only a few seconds later a beeping sound could be heard.

"Fuck!" Rei yelled, running to her computer. "Shit! Izuku, we need to go. Villain attacking downtown. Why now?"

Izuku grabbed his costume off of the table and pulled it on, using his quirk to  be faster. Rei grabbed hers and ran into the toilet, coming out a minute later.

Mirio stood up and stared at them. "Wait, you two are vigilantes?"

Izuku blinked at him. "Yes, but we're vigilantes who really need to go. There are lives to save. Please don't tell anyone. Eraserhead already knows, and he's gone with it. Uh, see you later?"

Rei burst throw the front door and Izuku floated through the wall, both heading off to save whoever needed them.

Toru sighed, watching Mirio as he stared at the wall where Izuku had disappeared.

"They really need to get better at hiding their identities."