My Hero Academia! One For All's Hidden Quirk

It was another chaotic day in Musutafu, Japan. Recent events have left the city in shambles, buildings destroyed, villains running wild, and the trust in heroes dwindling. Despite all this, our heroes are still out patrolling and protecting people. Izuku Midoriya (aka Deku), accompanied by two of his friends, Katsuki Bakugo (aka Great Explosion Murder God Dynamight) and Ochaco Uraraka (Aka Uravity), are patrolling the south side of town. Normally Bakugo would rather patrol alone, but rumor has it that a villain with a very powerful and deadly quirk had been spotted in this area. “Hey Midoriya, let’s hurry up and kick this guy's ass.” Midoriya looks out over the ledge of the building looking around for anything suspicious. “Calm down Bakugo, we don’t even know what this guy looks like.” Bakugo runs his hands like crazy through his hair while sitting there looking impatient and angry. Uraraka is sitting on the ledge looking down at her hands. “I hear his quirk is super dangerous, are we the right people for this?” “Of course, I’m the greatest hero, I’ll kill him!” He continued to ramble, while Izuku and Uraraka ignored him.

A couple hours go by, each of the heroes taking turns taking a break while the others watch the streets from their spot. Nothing happened until late that night. It was Uraraka’s turn to take a break and she was sound asleep. Due to growing bored Bakugo had gone off to patrol some other area, so when someone started yelling nearby, the only person close available to respond was Deku. Using blackwhip Deku flung himself into the air. Once in the air, he used float to soar through the sky in the direction the screams were coming from. It only took a matter of seconds before he reached the area. When he landed he found a very tall hooded figure attacking people. Deku called out over the comms to Bakugo and Uravity. “I think I found our guy, we’re in an alley about a kilometer to the west of our lookout spot. I’m going to engage with the target to draw his focus away from the civilians.”

“Alright, I’m on my way, please be careful.” “Damn, I’m in the opposite direction, I guess I’ll just have to go twice as fast, don’t you dare beat that punk, he’s all mine, you got that Deku!” With his teammates on the way, Deku approached the villain. The mysterious man seemed to have some sort of telekinesis ability, due to the fact that all the people around us were floating in the air around him. “Excuse me, sir, I’m going to need to leave those people alone, oh and also surrender.” The man turned towards Deku and stared at him. Due to his hood, Deku couldn’t see his face, so he had no idea what this guy was thinking. Deku was being cautious due to the hostages, but suddenly Deku’s danger sense went off. Deku quickly jumped into the air above all the buildings, the second after jumping the area where he was standing exploded. Somehow, this guy could also create explosions instantly, perhaps a sub-ability to his telekinesis.

This did pose a problem, as Deku had to keep moving. Each movement is followed by an explosion. Deku began thinking about a strategy, chances are this guy was a long-range fighter and probably weak to direct hits. So all Deku needed to do was get in close, very quickly. Which would be hard to do while under constant attack. Luckily that’s when Bakugo showed up, despite being twice as far as Uraraka, he still arrived first. “Hey Deku, what’s with all the running, this guy is too much for you?” “Bakugo, good thing you’re here, this guy can create massive explosions instantly, if I stop I’ll get hit. Do you think you can get him, while I distract him?” “Who do you think I am, of course I can get this punk.” Bakugo quickly builds up his power and explodes towards the guy at an incredible speed. When Bakugo got close to the man, he slammed what seemed to be an invisible wall.

Due to the force with which Bakugo hit this wall, he went flying backward. He landed on the ground, but he didn’t move or say anything. “Bakugo!!” “Dammit, he must have some sort of force field around himself.” “This guy really is dangerous. If Bakugo’s speed and strength didn’t break through I doubt my Fa Jin quirk will be able to.” Deku began to panic a bit, still constantly moving around. Deku and Uravitly don’t have any abilities that can pass through that force field. “Think Deku, think, there has to be something.” Deku began to ask the other one for all users if they had any ideas. None of them had any ideas, it seems like the only ability that would help was Aizawa’s eraser quirk. He was currently in the hospital and more than a little injured. So there was no way they could rely on him. There was always the kid from class 1-b, Neito Monoma. He had a copy quirk and could probably grab Aizawa’s.

That could take way too long though, chances are Deku would tire out before he arrived. No Deku needed a plan and he needed it now. As the situation became more desperate, the first and second users mentioned they might have a plan. “Really that’s great, what is it?” The second user started talking about a secret hidden user, the original third user. She had an ability called phase, it allowed her to phase out of this plane of existence and allow her to teleport while in this other plane. “That’s perfect, I could use that to get past his force field.” The first two users grew quiet, they mentioned that her quirk was sealed off due to her having a mutation quirk that they didn’t know about when they passed it on to all of them. “Whatever it is I’ll deal with it afterward, all that matters right now is saving those people and stopping this guy. As soon as he said this, the first user unsealed the hidden user, and with her came her phase ability.

As soon as she was unsealed, Deku was able to phase into another plane, taking a second to catch his breath now that he was safe from danger, even if it was for a moment. While sitting there Deku’s danger sense went off again. He looked around, but no one was there but him. That’s when his body started aching. “This must be that mutation they mentioned.” His body shrank a little bit, and most of the muscles he built up until this point disappeared. Next, his waist slammed down, his hair grew out a bit. His legs and butt felt like they got bigger. The last things were his chest, which ballooned out and became heavy and more sensitive, and his crotch, it had seemed like something down there went missing. After the pain disappeared and his danger sense went away, Deku opened his eyes. “What, what kind of mutation is this? I look like a girl.” The new user, Satsuki Tanaka (Aka Phaser), spoke up. "Well it’s a little more than a look, due to my mutation, you are one now.”

“We didn’t know about it until afterward, that's why I had Yoichi seal me off. Right now that’s not important though, you have people to save right?” Deku snapped out of it and used her new quirk to teleport near the villain while in the other plane. She returned to the normal plane and used one for all at forty-five percent and hit the villain, knocking him out. This caused all the hostages to start falling, but Uravity flew in and used her quirk just in time, so no one got hurt. “Deku? Is that you? What did that guy do to you?” Deku snapping back to her new situation turned red with embarrassment. “That’s a long story, I’ll tell you later, right now we need to get Bakugo and the civilians to a hospital.” After that, they arrested the man and threw him deep inside the Tartarus prison. All of the citizens that were being held hostage made out with only minor injuries. Bakugo broke both of his arms and several ribs but overall would be okay. Midoriya ended up stuck in her new very feminine form due to the mutation, they did try to seal Satsuki to see if it would reverse the effects, but in the end, they let her stay free so Midoriya could freely use her phase quirk. Luckily all of Midoriya’s friends supported her through this change. Her female friends helped her learn everything she needed about being a woman, like buying clothes and properly doing her hair. So overall Izumi Midoriya’s life didn’t change too much, she continued to train and become stronger, all in hopes of finally defeating All for one.