A Quirk Through Time/Villain Swap AU

Chrono Gate

All Might got off the phone with some other heroes. After being told about the training camp incident, he would've headed to the hospital, but Era happened to be standing in the doorway. He didn't remember their meeting and didn't know who the girl was.

"I'm sorry young miss, but we will have to talk another time. There is an emergency that needs my attention!"

Era stands aside as All Might opens the door behind her. What he saw wasn't the school hallways or even a building. Beyond the door was a path with trees lined on either side. He would stare down the walkway a few moments before closing the door, memories of their meeting returned to him.

"I'm not one to be ignored," Era said coldly "if you continue to do so, I'll send us back to the time we met."

"What is it you want to discuss, young Era," All Might had many questions, but the hospital was a priority for him.

"The long-term results of your desire ruined my future."

"If you know the future, couldn't you stop or warn others about these tragedies that killed the students?" All Might questioned.

She slowly shook her head. "Chrono Gate, my quirk, doesn't work like that. I practiced with my quirk, went through time, all to save a hero who I can't even remember now. It's like seeing a picture with a person cut from it, the event is the same, but the person is gone."

"If you can't remember the hero, maybe it means the event won't happen." All Might said, trying to be positive.

"It's hard to say, direct and indirect changes depending on the wish, they affect memories differently. Giving Tenko Shimura, One for All, was a direct change. Becoming the teacher of Class One-A instead of Aizawa was an indirect change." Era explained.

"I don't think I quite- hold on, how do you know about my quirk? Also, how would you know who would be in charge of Class One-A if it wasn't Shimura?" All Might became fully invested in the conversation.

Anyone who knew the secret of One for All, couldn't be ignored.

"You retained some memories of the other you, but where do you think the other memories go? I'm the gate that connects you, to you. You pay the toll, pass through the gate with what you need, and the rest stay with me. It isn't that convenient usually. I only know what happens during the other timeline when you learn those same events here. From when I sent you back to now, I know everything you knew." Era took a seat nearby as she glanced out the window.

Era continued as if talking to herself. "The problem becomes, your memories suffer the same flaws mine do. Things that were directly changed by your wish are cut out, like the person you should've met last spring. I don't know anything about them, but almost every memory you have beyond that spring involves this person."

"You know it's the same person?" All Might became curious about this other person.

"It's too much of a coincidence for it to be different people all the time." Era answered. "Wait, too much of a coincidence," Her eyes widened as it dawned on her. "Are they the same person?"

"The person I never met in the spring, and the hero you can't remember?" All Might asks.

"Yes, if they are, then I have to undo your wish immediately." Era said as she started to panic.

"Why immediately?" All Might didn't want to lose Shimura.

"I can only undo my quirk if we're in the same area. Should you die, I'm no longer able to undo this timeline. The other problem is my birth. I'll be born in this timeline in fifteen years or so, and when I'm old enough to get my quirk, the current me will disappear. I'll remember some of these memories as I get older, but I'll lose any contradicting memories. I can't remember anything about a person if I never met them." Era laments.

"If you aren't born yet, what would it mean for the others who see you now?"

"A quirk that affects time cannot be affected by time," She stood up and moved the chair away from the window before sitting down again. From All Might's perspective, the chair never moved, and now she was floating in the air. "I'm trapped in a time-bubble my quirk creates. I can't interact with anything, and no one can interact with me. There are a few exceptions, like how we met and right now."

"Why don't we go back again? Maybe we can find the person you're looking for, and we can save multiple students who lost their lives," All Might says.

"I can't use my quirk on the same person twice. The cost would probably be too great anyway." Era thinks to herself a bit. "If the person I'm looking for is living a happy life, I guess I don't mind keeping this timeline."

"Well, if you find any other information in my memories, I'll help any way I can," Believing the conversation was over, All Might tried to leave again.

"One last thing, who is Izuku?" Era asked.

"I don't think I understand the question."

"No one named Izuku took the hero exam in your memories, and yet he had the highest score. More importantly, I'm sure he noticed me."

"Maybe your quirk is responding to his desire to save his mother?"

"My quirk can't directly prevent death; The cost of life would be a life. It's why I was trying to save my hero indirectly."

"Yea, he was also a kid. If you sent him back, he wouldn't be able to stop the villain." All Might sighed.

"I've kept you long enough for today. Go to your students, but make sure to come back. After your trip to the hospital, we still have much more to discuss." Era stated as All Might nodded and headed to the hospital.

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The name Chrono Gate comes from a combination, Chrono Trigger and Stiens Gate.