Chapter One:

Izuku lay on his back staring at the blue sky. The steel spike impaling his midsection had stopped hurting. That probably meant he'd gone into shock.

All for One and All Might's corpses lay on either side of him. What a strange symmetry. All for One had killed All Might during the final clash between heroes and villains. Then Izuku had killed All for One. He didn't regret it, exactly—he'd done what he had to in order to save all of his friends. But he still felt tormented by the crime of killing his own father.

How would he explain this to Mom, who loved her husband without knowing his true identity? He wouldn't have to explain it if he died. Poor Mom, losing both her husband and her son in one day.

The hazy form of the First One for All user appeared over him. Tears dripped down his translucent cheeks. Yoichi whispered, "Izuku…"

"I'm dying. I know." Each word strained Izuku's throat. He tried to smile. "At least I fulfilled the wish of One for All. I defeated All for One and saved all my friends. Everyone except…" He couldn't bring himself to speak All Might's name.

"None of us vestiges want to see it end like this." Yoichi bit his lip. "That's why we've pooled together all of our power to offer you a wish."

The sky overhead blurred and twisted. Izuku felt his eyes start to close. He barely managed to speak. "A wish?"

"We're not sure how it works either. But One for All is a very strange quirk. It was born out of my greatest desire. At times, it's often warped itself to fit what each user wanted. It granted the Eighth a more muscular body because that was his ideal and gave you more quirks because you had such a strong passion for them. None of us completely understand how it works, but we think we can grant your most heartfelt wish. Hopefully, that wish will save your life."

"I don't want to die." Izuku felt tears trickle down his cheeks as soon as he admitted this. "Even more, I don't want All Might to be dead."

"I have no idea if One for All can bring back the dead." Yoichi met his eyes with a blazing green gaze. "Let's try."

Izuku reached for the ghost's outstretched hand. Instead of flesh, he felt an electric spark. It raged through his body and ripped one last scream from his throat.

All Might woke up on a futon.

He was dead. He'd been certain of it. All for One had ripped his heart clean out of his body! He still remembered the horrified look in young Midoriya's eyes as he'd been forced to watch. Even Recovery Girl couldn't have saved him at that point.

But he didn't feel dead. His back hurt slightly from lying on a knot in the wooden floor. The ceiling fan overhead rattled. The scent of bacon drifted through the door. It was all too mundane to be the afterlife.

All Might stood up and shook the crick from his neck. Aside from having slept a little funny, he felt better than he had in years. Ever since his injuries at All for One's hands, he'd had trouble breathing. But now he felt as young and fit as a twenty-year-old. Even more strangely, the power of One for All crackled under his skin as strongly as ever, not the faded ember he'd once had.

Voices came from the next room. Hopefully they could answer his questions. He opened the door.

Inko Midoriya set down a plate of bacon and scrambled eggs on the dining room table. "Breakfast is served."

"Thanks, Mom," Izuku said.

"It smells delicious, darling," a deep voice said.

At that third voice, every muscle in All Might's body went rigid. That white, curly hair. Those crimson black eyes. The face healed into the handsome features he'd seen for years in his nightmares. That melodious, mocking voice. All for One.

He moved on instinct. Raising a fist, he charged towards his enemy.

His feet refused to move. He swayed awkwardly with one fist raised.

Inko looked up, smiling. "Toshinori, you're awake! Please join us for breakfast."

"Yeah, stop standing there like you're about to swat a fly and come eat, Dad," Izuku chimed in.

Dad? Dad. Young Midoriya had called him Dad. All Might's brain short-circuited with happiness. A warm feeling formed under his chest. He was starting to doubt his earlier conclusion that this couldn't be heaven.

Except for the presence of the final person in the room…

"Dad?" Hisashi Midoriya frowned. "But I'm your father." He turned his head. As his gaze fell on All Might, his face froze. He leapt to his feet, hand raised to summon his many quirks.

Then he stopped moving. His eyes darted around as his head remained rigid. All Might could immediately guess that his nemesis was under the same curse as himself.

"Whoa, you two are making such funny poses." Izuku laughed. "You're both my fathers." He said this as if it was completely normal. There was no trace of deception on his face. Not that young Midoriya had ever been much of a liar. He genuinely believed this.

All Might felt faint.

Inko waved toward the table. "Please, sit while the food is still hot." She seemed to find this entire situation as normal as Izuku did.

"Don't any of you remember?" All Might whispered.

"What? Is today some special day?" Izuku cocked his head.

"Remember—" the final showdown against All for One, he tried to say, but the words wouldn't emerge from his throat. His mouth stopped moving exactly like his fist.

Then the whole world froze in time. The ghost of the First One for All user appeared before him, his hair dishelmed and his eyes haggard. "I'm so glad you're awake, Eighth! And that you have your memories."

"So this isn't a dream," All Might said.

"It's a wish." Yoichi pushed his hair out of his eye. "Nineth was dying at the end of his battle. We tried to save him by using One for All's power to grant his deepest desire."

"Which was…this?" All Might waved at the happy family breakfast frozen in place.

Yoichi winced. "I didn't see it coming, either. Who would have thought that Izuku would want All for One in his life? Pretty much anyone who meets my brother tries to get as far away from him as possible. That goes double for his family. The Second has a theory that maybe Izuku just felt guilty about committing patricide no matter how badly the bastard deserved it. The Third thinks Izuku did it to make his mother happy."

"If you did this, then you ought to fix it." All Might glared. "Restore everyone's memories. Get rid of him." He pointed at the motionless All for One. "Or at least let me punch him!"

"We don't know how to do that." Yoichi sighed. "We used up over a century of power to grant Nineth's wish. We've got nothing left."

"How useful to know," Hisashi said.

All Might leapt nearly a foot in the air. "How did you unfreeze yourself?"

"I was faking it to listen to your conversation." Hisashi smiled. "I think both of us are immune to the memory altering and the time-stopping because we're One for All users. Yes, I did hold the quirk before passing it to my brother, if only briefly, making me number zero. As for my son, I would speculate that he forgot because he'd be happier that way." His smile widened. "How lovely to see you again, little brother."

Yoichi edged away. "I'm out of here. Good luck with him, Eighth."

"Hey, stop!" All Might shouted. "Don't leave me to deal with this mess by myself!"

"Sorry, I can't hear you. You're breaking up."

"Do you think I'd believe such a cheap trick? Get back here! This is all your fault, don't bail on me!"

Still pretending not to hear, the ghost vanished.

The air shifted, becoming mobile. Izuku asked, "Remember what?"

"Uh. Nothing. I must still be sleep-deprived." All Might shifted from foot to foot. He couldn't just sit down and eat with his greatest enemy, but he couldn't leave Inko and Izuku alone with the villain either. In the end, his protectiveness won out.

He sat down and picked up his fork. But he couldn't make himself vulnerable by eating when he felt hyper-aware of his archnemesis sitting next to him.

Hisashi dug into the meal without a trace of any such qualms. "Your cooking is as wonderful as ever, my dear."

Inko giggled and flushed. "Thank you. I'm so glad you were transferred back from America so we can spend more time with you."

All Might groaned.

Hisashi smirked. "Family is important to me! I'd never abandon you two. I remember a story about a useless woman who put her son up for adoption because she couldn't handle her responsibilities. Then her son was murdered and her grandson was adopted by a villain and turned into a weapon against her legacy. What a pathetic, useless fake of a hero."

"Why, you…" The fork snapped between All Might's fingers. He leapt to his feet, fighting against the compulsion as he desperately tried to rip All for One's face off a second time.

Inko frowned. "What's wrong, Toshinori? You're acting so strange. You almost seem to be…menacing Hisashi." Her voice hardened.

Hisashi said, "I don't mind. I was just about to tell you the disgraceful story of how that woman died a dog's death."

A hiss emerged from All Might's clenched teeth. He knew full well that All for One was provoking him to make him look bad in front of Inko and Izuku. But he couldn't bring himself to idly sit by and watch Nana be insulted.

If he couldn't use his fists, then he'd use words to strike back. He sat down. "I'm sorry, I saw a fly." His smile looked deeply insincere. "Your story about lousy family members reminded me of an evil villain who murdered his own younger brother."

Hisashi's smile fell off his face. "That's a gross misrepresentation of what happened!"

"Oh, I'm sorry, did I strike a nerve? My story had nothing to do with you, obviously. You're a true family man who came back from America to spend more time with us." All Might carefully watched his enemy's face. "Unless, of course, the real reason you came back was because your business failed. Maybe you abruptly stopped being able to carry out your usual work? Almost like magic?"

All for One's jaw twitched. Just barely, but it was enough to give him away. All Might's suspicion had been right: his old enemy couldn't carry out his villainy any longer, any more than they could attack each other.

Izuku frowned. His tone became stern. "I'm not sure what's going on, but I want both of you to drop it. Usually, you get along so well. Father, did you fight with Dad?"

Hisashi mumbled, "I don't understand why he got the Dad title."

"Because he had it first. We agreed on this. Dad is my biological father—" Izuku pointed at All Might. "And Father is my stepfather who married Mom after her divorce."

Hisashi went rigid from head to toe. Horror slowly crept down his face. It was beautiful to behold. "S-stepfather?"

"It's great how well you get along with Izuku despite not being biologically related." Inko kissed her husband's cheek.

All Might laughed loudly, thrilled both by Hisashi's demotion and his own promotion. "I guess Izuku must have wished for such an arrangement." He knew his enemy would understand his malicious implication: Izuku had removed Hisashi from the position of biological father for a reason. They both understood what this said about how Izuku must have felt at the end of his life.

Hisashi's eyes shot around frantically. "Surely I'm not the only one who sees this doesn't make sense! We look so much alike." He gestured between his and Izuku's admittedly very similar faces. "We have the same hair curly hair and freckles! I demand a DNA test!"

Izuku laughed. "That's just a coincidence. See how much I look like Dad?" His eyebrows bristled and his teeth gleamed in his trademark imitation All Might face.

All Might laughed so hard he choked. "That's right! I'm so proud of my son."

Hisashi glared in a way that spelled murder. But there was nothing he could do, and they both knew it.

This was the start of the Dad Wars.

After breakfast, Hisashi said, "I have the whole day free to spend time with you, Izuku. Would you like to visit a museum or perhaps play polo?"

"Sorry, Izuku and I already have plans." All Might pulled out a TV guide. "There's a marathon of old superhero movies on."

Izuku bit his lip. "I am sorry, but I've been looking forward to the movies for weeks. You're welcome to join us."

"That's right, you're welcome to join us." All Might pulled out his and Izuku's matching All Might hoodies. "You can spend six straight hours sitting next to us as we fanboy over heroes. Look, I even brought a spare hoodie for you."

"That's right!" Izuku cheered. "If you're watching a hero movie marathon, you have to wear All Might merchandise. House rules!"

Hisashi looked like he'd had a lemon crammed down his throat. "Despite your…tempting…offer, I'll have to pass."

After they paused their marathon for lunch, Izuku boiled a kettle of tea. He poured All Might a cup. "Here's your favorite mug, Dad." The mug was covered in sparkles and had "Number One Best Dad" painted in a childish scrawl.

Standing next to the fridge, Hisashi whirled around. "Hey! That's my favorite mug! You made it for me in art class when you were seven. It's been my greatest treasure ever since."

Izuku tilted his head, eyes widening in confusion. "You must be remembering wrong. I gave that mug to Dad when I was seven. I hadn't even met you back then."

"That's right. I love this mug." All Might took a long, satisfied sip.

Hisashi's knuckles turned white around the fridge door handle. His eyes burned with loathing.

Over dinner, Hisashi asked, "Izuku, would you like to analyze the group of professional heroes visiting from Korea? I thought several had interesting quirks."

Izuku's eyes lit up. "I know! Especially Stormdancer."

Hisashi nodded. "I've never seen a combination of a weather and a strength ability."

"Is it dual ability like Shouto's or are they linked? She dances to summon storms. I think they're linked." Izuku started mumbling.

The subsequent quirk analysis went over All Might's head. As Hisashi had intended, he was left completely out of the conversation. But he still had a trump card to play.

All Might cleared his throat. "I've met all the Korean heroes before. I even saved Stormdancer's life."

"Really?" Izuku's head shot up. "I'd love to hear that story!"

"How about I tell you it when I introduce you to her tomorrow? She owes me a favor. She'd be happy to answer any questions you have about her quirk."

Izuku beamed. "You're the best, Dad!"

Hisashi glared with increasingly bloodshot eyes.

All Might grinned at his old enemy. Initially he'd thought this was a fate worse than death, but now he was starting to see how every disaster had a bright side.

The next morning, a truckload of gifts arrived.

"What brought this on, darling?" Inko asked as the moving men carried the boxes inside.

"I just felt like spoiling my family." Hisashi kissed her neck before hanging a diamond necklace around it.

"Oh, whoa!" Izuku opened the boxes to reveal everything from a new gaming system to a silk tuxedo to a set of weights. "This is amazing, Father. Thank you so much."

Hisashi beamed. "Anything for you, son." His fingers petted Izuku's curls possessively.

All Might cleared his throat. "I had a gift for you too, but it's just a little thing. Now I feel bad about presenting it."

"Don't worry, I'm sure I'll love it." Izuku bounced over.

From behind his back, All Might pulled out a figurine of Nana Shimura. "I know it's a bit battered, but—"

"It's Grandma Nana's very first every hero merchandise!" Izuku gasped. "Where did you get this? Only a couple hundred were ever made."

"Of course, I was her fan from even before I met her. I scrimped and saved my allowance to preorder this." All Might smiled. "For a long time, it's been my greatest treasure. But I want you to have it now. Because you're carrying on her legacy. More importantly, you're my greatest treasure now, my son."

"Thank you so much, Dad! I'll treasure this for the rest of my life!" Izuku clutched the figurine. He threw himself into All Might's arms and wept until both of their shirts were soaked. There was no denying that this gift had meant more to him than all of Hisashi's expensive presents.

Looking over Izuku's head, All Might smirked.

All for One looked like a man driven to the brink of madness. His fingers twitched sporadically. But he couldn't do a single thing. It was so satisfying that All Might wanted to break out into song like a Disney character.

The minute they were alone, Hisashi backed All Might against a wall. "You realize this means war."

Let the villain bluster and threaten. All Might knew he'd already won in the most important way. He smiled—his first sincere, pain-free, unpressured smile in years. "Bring it, potato head."

OMAKE TIME!

Omake: The First Has His Limits

All Might: I can't believe you ran away like a coward!

Yoichi: Look, if you were to face my brother in battle then I'd stand with you to the end. But having a family breakfast with him? You're on your own.

#

Omake: This Wish was Also a Certain Conspiracy Theorist's Dream Come True

Shouto: All Might is your father?

Izuku: Yes. It's not a secret. He introduced himself as my father on the first day of class. Everyone knows.

Shouto: For some reason I have a strange urge to jump up and down and scream, "Yes! I knew it! I told you all so!"

#

Omake: DNA Test

Doctor: We have the results back on the DNA test you requested. Izuku Yagi is Toshinori's blood-related son. He has no relation to you at all.

Hisashi: Stop calling him Izuku Yagi! That can't be true! He looks exactly like me and nothing like the blond poser.

Doctor: It is very odd, given how much DNA you share with Izuku and how he has no overlap with Toshinori Yagi.

Hisashi: Uh…could you repeat what you just said and then ask yourself if it makes any sense?

Doctor: But DNA tests don't lie!

Hisashi: Give me a moment. (Pulls out a locket with a lock of white hair inside.) This is my younger brother's hair. Could you run another test on this for both me and Izuku?

Later:

Doctor: The hair sample you gave me belongs to Izuku's uncle and your brother. But there's still no relation between you and Izuku.

Hisashi: That's not how genetics work. Surely you see that.

Doctor: It's theoretically possible if we assume that you and Toshinori Yagi share a common half-brother who's related to both of you through a different parent.

Hisashi: Except we don't! My brother died long before the smiley bastard was ever born, and we had the same mother and father. This. Isn't. Right. Is your medical degree just a piece of paper?

Doctor: I'm sorry about your strange family tree, but you can't get angry at me just because you don't like your DNA test results.

Hisashi: Grrrrr.

Author's Note: The title of this fic is an ancient Chinese curse, which means roughly the equivalent of "be careful what you wish for."

Just imagine how frustrated the One for All users would be to finally see All for One dead, then accidentally revive him themselves. But the more they see him furious because he can't commit villainy any longer and the more they watch him being tormented by All Might, the more they'll come around to this punishment instead.

By the way, one possible alternative interpretation of this fic is that Izuku remembers everything (because he's a One for All user too) and he's playing along with All Might in order to make his bio dad justly suffer.

The second chapter of this twoshot will be posted next Friday. Since Kill What You Love has taken over my Thursday update slot, I'll sometimes drop a surprise oneshot on Fridays instead, but I can't promise to update every week since I'm currently working on three stories at once.

Next chapter, an unexpected past One for All user will offer All Might assistance in driving All for One crazy.