Author's Note: Happy Birthday Tsuyu Asui! I got her the usual gift—All for One as a father. Tsuyu has a different canon father, Ganma Asui, but for the purposes of this fic, he doesn't exist. I named her father Hisashi to make it clear he is a different guy from Ganma and because that's the name I always use for All for One. However this fic is not Dad for One as yanderes are generally not cheaters. This takes place in an alternate universe due to divergent events pre-canon. Thank you to Gfan97 for this fun fic idea.
Tsuyu Asui had a lovely and kind mother, two adorable younger siblings, and the single most annoying father in existence. Her mother Beru had a high-paying consulting job that frequently required her to travel, often sending her abroad for weeks at a time. As a result, her father Hisashi had become a stay-at-home dad. And Hisashi Asui was a truly loving and devoted father. He made the children their favorite meals, he'd memorized their favorite bedtime stories (even though he kept rewriting the ending so the villains won), he'd learned how to braid hair for his daughters, and he praised his children for even the smallest things. But he did not believe in the concept of space. Since he did not work, make friends, or have time-consuming hobbies, he was there every single waking moment after they got home from school. He wanted to be with his children constantly. Children's games were his favorite kind. He insisted on helping them with their homework. When Tsuyu had joined the volleyball team at the start of middle school, he'd gotten himself made coach through dubious means. He'd been chaperone on every single field trip because he didn't trust anyone else to look after his kids. Tsuyu loved her father, but she was nearly ready to murder him and bury his body in the backyard just to get some time to herself.
On her birthday, Tsuyu went out for bubble tea after school with her friend Habuko Mongoose. It was not an option to invite Habuko over for a birthday party, because her dad would flip out if he learned his beloved frog daughter was best friends with a snake heteromorph. Hisashi saw danger to his family absolutely everywhere. Tsuyu didn't have any other friends to invite over, so instead she planned to have a small birthday dinner with family. The other kids at school tended to ignore her. She knew it was because of her mutation since the same happened to Habuko. However, she told her father that she didn't hang out with inferior children. That was an explanation he would believe. She shuddered to think about what would happen if Hisashi ever learned the truth. He'd once told her that if anyone ever bullied her then he would burn her school down with everyone locked inside. It had not sounded like a joke.
When Tsuyu got home, she took off her shoes, then set down the manga book that Habuko had given her. As soon as her arms were free, her younger siblings ran out to hug her, crying, "Happy Birthday!"
Her brother Samidare whispered, "Please do something about Dad. He's been extra clingy since you weren't home. He checked your location on his phone every five minutes, then the rest of the time he would just stare at us as if we might vanish."
Satsuki, the youngest child, buried her face in Tsuyu's shoulder and said, "Dad did my hair fifteen times this afternoon. I begged him to leave my pigtails alone but he said no hairstyle was good enough for his little tadpole."
Tsuyu sighed. It sounded like her father was in a maniac mood today. When he got like that, he became the most difficult to handle.
Dad ran into the hallway. "Tadpole! You're finally home. Happy birthday." He lifted her off her feet in a hug. "I was about to call Gigantomachia to fetch you."
Tsuyu rolled her eyes. "Dad, you knew I'd be out with a friend today. I'm home early." She always told her father she'd be home later than she actually planned because if she didn't arrive early, he would flip out. Tsuyu had fun playing with her massive babysitter, but Gigantomachia would be a disaster roaming the city. "Please, it's my birthday, can't I spend a little time with a friend?"
Dad sniffed. "I can't understand why you'd want to associate with a mere middle school brat when you could be spending time with your family. But you're here now!" His mercurial smile returned. "Let's play board games as a family."
Behind their father, Samidare and Satsuki gagged, made faces, and shook their heads.
Tsuyu said, "I have another present I want from these two. Since it's my birthday, I want you to go into the vault obediently."
Clearly trying not to smile, Samidare said, "Okay!" Satsuki nodded and jiggled. She was too young to hide her happy expression.
Tsuyu ushered her siblings down the stairs to the giant vault in the basement. The metal room had been furnished with a TV, a PlayStation, a computer, and a chest full of toys. Samidare and Satsuki eagerly ran in and started bouncing on the couch.
"Stay in there until I let you out," Tsuyu said. For some strange reason, her father loved locking relatives into vaults. His children had quickly realized this was the only way to get some alone time. The vault was stuffed full of entertainment so no one minded staying there. Tsuyu only wished she could go in and lock the door, too. Unfortunately, Hisashi thought that vaults were for older siblings to contain younger ones. Ever since the younger two children had been born, he'd stopped locking Tsuyu up in there. What a shame. She missed the vault (and privacy) so much she had dreams about it.
As the door closed, Dad applauded. "My dear tadpole, I'm impressed. You've got your younger siblings so broken they just hop right into the vault. This all must be thanks to me teaching you to be a good older sister."
"Uh-huh," Tsuyu said neutrally. Personally she credited her great relationship with her siblings with doing the opposite of whatever her father said. He was full of bad advice like "kick them in the head if they talk back." Not that Dad was ever violent himself, but he believed in the superiority of older siblings over younger ones to a creepy degree.
"They even seem to love you more when you vault them. I've never heard of such astonishingly sensible younger siblings. It must be all because of my great genetic material and parenting abilities."
"Uh-huh." Her dad was sweet if a goofball, and she feared it would break his heart if he ever realized his children went into the vault to avoid him. Still, she could not resist casting a longing glance at the steel door as they left the basement. The vault was the only safe space from his smothering. Tsuyu loved her dad, she really did. She just needed space. It was a natural desire for a teenager, but try telling that to her father.
Dad continued, "Yoichi was always more difficult—of course, I'm sure I would have broken his will if only I'd been able to keep him inside a bit longer."
"That's nice," Tsuyu said. She believed Yoichi to be her father's imaginary friend from childhood. Hisashi liked to tell all kinds of ridiculous stories such as saving Yoichi from nearly being eaten by rats when they were both babies. Tsuyu was far too old to believe in such fairy tales. Hisashi also sometimes talked to someone he referred to as her grandmother. Apparently some people never outgrew imaginary friends.
"Younger siblings can be very ungrateful, you got lucky." Unfortunately this got Dad off on a tangent about his Absolute Worst Childhood Ever where if he wanted food, he had to kill someone and steal it. Tsuyu had never been sure if her father went on these rants to entertain her and parody the standard old people Back in My Day speech, or if he actually expected her to believe his ridiculous exaggerations. Sometimes he pretended he'd been born during the dawn of the age of quirks. Surely he couldn't possibly expect her to believe that?
Dad said, "I've already sent Kurogiri to pick up your birthday feast from chefs around the world. I would have cooked myself, but I knew you'd want to spend all your time with me on your special day. The greatest gift of all is myself."
Tsuyu's eye twitched. "Uh…I have homework…"
"I'll pay someone else to do it," Dad said, waving his hand. "No need to thank me, it's your birthday. Oh, and I got you a very special gift."
"Is it another quirk?" Tsuyu mumbled. She would have preferred twenty minutes alone.
Her father had the ability to give and take quirks. Since childhood, he'd loaded her down with different powers. Including an immortality ability, but that one might be fake? She hadn't seen any evidence of it yet. He did not ask for permission first. So far he'd given her enhanced healing, an ability to last without sleep for long periods of time, increased stamina, premonitions of people who might harm her, a teleportation power that only activated under life-threatening circumstances, and a camouflage ability (which she passed off as part of her mutation.) He seemed absolutely obsessed with giving her powers to keep her safe.
"You've already guessed the best part, I can't keep it secret." Dad smiled widely. "I found an ability to allow you to speak to family members from a distance, so that you can be in constant contact with me. I'll never need to worry about you being out late again."
Tsuyu closed her eyes and prayed for patience. "Um. That ability seems…unnecessary…with all the others. I could have sworn I asked you for a new jacket."
Dismissively, Dad said, "Oh, I got you that too, and a few dozen other gifts, but another quirk to ensure your safety is the prize present."
Tsuyu couldn't allow this to happen. She'd never get a free moment again. Her father would expect her to be in contact with him every minute of the day. But if Hisashi kept the ability, it would be even worse, because then he could constantly chatter at her. She'd been trapped.
Dad clapped his hands. "With the younger two safely in the vault, I have you all to myself! Sometimes I miss work, but luckily I have you kids to keep me busy. I have such an exciting plan for your birthday. First we'll analyze quirks online. Then I'll trounce you at Monopoly as usual. After dinner, we're going to watch the video I made of Captain Hero highlights. Then you can listen to my lecture about why the Demon King should have won—it's a different lecture this year, I made the PowerPoint interactive. As the highlight, I got you a new Demon Queen cosplay—oops! I spoiled another birthday present! Oh well, we'd better get started, I have a lot planned."
"Ribbit," Tsuyu said sadly.
Needless to say, the birthday afternoon was dreadfully dull. Hisashi Asui sincerely meant well, but he did not seem able to grasp the concept of other people having different likes and interests than himself. Tsuyu did not care about Captain Hero. Her father remained convinced she was a fan despite her telling him otherwise to his face. She didn't like Monopoly or quirk analysis either. After an afternoon of both, her patience had reached its limit. To make matters worse, her father could never resist talking about how he'd sacrificed his career to stay at home and look after his children. He claimed to have greatly enjoyed his work. Even though he was vague on what career, he expected them all to be very grateful.
Hmm, that gave Tsuyu an idea. Could she persuade her father to return to work? Perhaps if he had an interest outside home, he'd be less insanely controlling and possessive. He'd be too busy to check up on her all the time. It would be win-win since Hisashi would get to return to his beloved old job. Tsuyu was old enough to look after her siblings. In fact, she didn't even need to be paid for babysitting if it would just get her dad out of the house before she went insane and stabbed him with his own replica of the Demon King's sword.
Maybe Tsuyu should appeal to her father's ego instead of her own needs. Though Hisashi often claimed to be logical, he was in fact a hypocrite, extremely emotional, and a massive manchild. After her miserable afternoon, she was desperate enough to try.
Although Kurogiri had purchased all the food for dinner, Hisashi liked to set it out on the table so he could take credit. (Kurogiri did almost all of the household labor.) While Hisashi was busy, Tsuyu ran to the basement and whispered a plan with her siblings.
Their mother Beru arrived home just in time for the dinner. It smelled amazing. Although Tsuyu might complain about her father, she had to admit he'd prepared a feast, including ten different flavors of jelly. He loved spoiling his children. The whole family sang the happy birthday song as Hisashi brought out a ten-tier cake with flavors of vanilla, chocolate, and strawberry.
When they were all stuffed, Tsuyu sprung her plan. "Dad, you've gotten me so many great gifts for my birthday, I want to give you one in return."
"How sweet, my tadpole." Dad beamed. He was the kind of person who thought nothing of getting a gift on someone else's birthday.
Tsuyu took a deep breath. "I'd like to look after my siblings, so you have the freedom to return to your job."
Dad blinked. "Oh, but I promised your mother I'd stay at home until all three of you reached age eighteen."
Beru nodded. "It was our agreement when he wanted a third child. I love my work too much to take time off."
Tsuyu clasped her hands together. "You're a wonderful father, but seeing your brilliant PowerPoint on the Demon King made me realize that your talents are wasted staying at home. I can look after Samidare and Satsuki by myself. You saw how obediently they go into the vault."
Samidare said, "Dad, we want you to be happy and chase after your dreams."
Satsuki nodded. "We'll root you on!"
Beru shrugged. "If it's what the children want, then I don't mind altering the terms of our deal."
Dad wiped a tear of joy from his eye. "It feels wonderful to have such a supportive family. Unlike my horribly ungrateful little brother. I always knew Yoichi was the problem and I was perfect. I've never been so happy before! For the sake of my family, I'll conquer Japan."
Everyone cheered, even Tsuyu, though she was a little confused. What did her dad mean about conquering Japan? Was it a metaphor? But for what?
Oh, well, her plan had worked, and she'd finally have peace and quiet.
Later that evening, Tsuyu caught her mother alone reading in the living room. She asked, "What was Dad's old job?"
Setting down her book, Beru said, "Your father used to be the predominant villain in Japan."
Tsuyu laughed so hard she slapped her knees. "Good one! You said it with a straight face, too. Seriously, what's Dad's job?"
"I am serious, Tsu. Your father is an immortal villain from the dawn of the age of quirks. His goal is to murder All Might, steal his quirk, and take over Japan—not necessarily in that order. We met in jail. I was in prison for my work for the Frog Supremacy Front—"
"Isn't that a terrorist organization and cult that believes we should all worship frogs and rip down society in order to build giant ponds?"
Beru said serenely, "It's only natural for our family to side with our frog brethren around the world."
Tsuyu gaped. As she put together a million comments from her mother that she'd taken as jokes, she started to realize this might be real. "Then when Dad says that he wants to conquer Japan…he actually wants to conquer Japan!?"
"Of course. You had great timing persuading him to return to work, if you want to be the future Princess of Japan. All Might currently doesn't have a successor. Now is the ideal moment to attack." Beru smiled. "No need to look so shocked, Tsuyu. Your father was always going to take over Japan, you just sped up the timeline. He promised me a frog temple in every town, won't that be lovely?"
Tsuyu swayed. She'd made a horrible mistake. In a very small voice, she asked, "What if I can't handle my siblings alone after all? What if I need Dad's help?"
"It's too late now, silly. Your father already mailed a declaration of his return to All Might." Beru patted her daughter's hand. "You're going to make a great evil princess, you already have the cosplay."
Tsuyu toppled over in a faint.
Months later, Tsuyu stood at the gates of U.A., ready to take the entrance exam. Her hands tightened on her backpack straps as she gazed up with determination. It hadn't been easy to persuade her parents. She'd pretended she wanted to spy for her dad.
In reality, Tsuyu was here to do her part to stop All for One. She couldn't let Japan be destroyed just because she'd needed some space from her dad!
OMAKE TIME!
Tsuyu: Kids at school are ignoring me because of my mutation—
All for One: I'll give you a quirk to stab them.
Tsuyu: Uh, on second thought I'm just a natural loner.
All for One: Great, I didn't want to have to give up your grandmother.
#
All for One: Imagine the scandal if a middle school principal was caught seeing escorts. If you want me to keep this quiet, you owe me a favor.
Principal: Please, I'll do anything! You can have all my money, just don't tell my wife!
All for One: I want to be made coach of my daughter's volleyball team so I can spend more time with her.
Principal: That's all?
All for One: I don't have any volleyball experience. I don't even know the rules.
Principal: No one else volunteered. You could have gotten the job by applying normally.
All for One: Can I use my quirks on the opposing team as long as no one notices?
Principal: Again, you didn't need to blackmail me, I would have encouraged you to make us number one using any means necessary.
#
Shouto: Izuku is All Might's lovechild.
Izuku: I'm not!
Tsuyu: I saw you use multiple quirks. Trust me, you want to go with All Might. He's your only good option here.
#
Tsuyu: I'm pretty sure my father uses a quirk to increase his height, since none of his kids came out tall.
All Might: This is fascinating dirt, please continue.
#
Katsuki: Why did you kidnap me from the Training Camp?
All for One: You have spiky hair so you must be trying to date my daughter!
Katsuki: Who?
All for One: My adorable tadpole princess.
Katsuki: Do you mean the filthy toad?
All for One: Well, now you're dying either way.
#
Izuku: We need to rescue Kacchan!
Tsuyu: Eh, there's no need. My dad told me that Katsuki Bakugo is his other spy. He probably faked the kidnapping for a debriefing.
Izuku: Kacchan, a spy? Have you seen him act subtle, ever?
Tsuyu: …Dad lied to me!
All for One: Anything to keep you away from spiky-haired people, my tadpole.
#
Yoichi: I can't believe you and your siblings like the vault. You've failed me.
Tsuyu: It's the only time our father leaves us alone.
Yoichi: Fair. In my case, big brother kept coming inside to gloat, force metapowers on me, etc. The most unbearable part of the vault was definitely his presence.
#
Tsuyu: I was shocked to learn that Yoichi is real! So is my uncle as dramatic as my dad?
Izuku: Arguably worse. He gives monologues from straight out of a comic book.
Tsuyu: Yeah, my dad also mistakes comics for real life. In elementary school, I went to class cosplaying as a different character every day. My teachers let it slide because my dad donated so much money to the school. I live in fear that he'll blackmail me with the pictures, but fortunately he doesn't realize it was anything embarrassing.
Izuku: You still have more dignity than those two brothers ever will, combined.
Yoichi: Hey! I believed in you, Ninth.
#
All for One: My dear tadpole! It's me, your father, possessing Tomura Shigaraki's body.
Tsuyu: Ugh. I don't know you. My dad isn't an insufferable gamer who hasn't showered in four months.
All for One: I could bring out the baby stories to convince you—
Tsuyu: No! I was pretending not to recognize you because you're too embarrassing. Don't you dare bring up my childhood stories when you're in Tomura's body and he might hear.
All for One: Don't worry, he's not conscious. Probably.
Tsuyu: That's even more horrible!
All for One: He passed out from shock when you eviscerated his showering skills. You're not wrong, by the way. I really need to clean this body up before I go visit your mother.
Tsuyu: Please stop making it creepier!
#
Tsuyu: I have to prevent Toga from revealing Ochaco's feelings because that will ruin her big confession moment! It might interrupt the whole flow of this storyline so that we get stuck in this annoying arc.
Ochaco: Uh…I thought you were being a supportive friend but I'm starting to get confused at your overinvestment in my love life…you realize that life isn't a shoujo manga?
Tsuyu: Well, for me it is. When I was four years old, my dad told me that I needed to pick which genre I wanted to live in. I picked shoujo because it only seemed sensible. After all I don't want to have to fight aliens or yokai. Oh, no, people don't normally live in manga genres, do they?
Ochaco: Nope.
Tsuyu: Curse you, Dad!