Summary: After an unfortunate accident at school, Sawada Tsunayoshi was placed into a medically induced coma at the tender age of ten. Three weeks later, he woke up a completely different person with no recollection of his life. The doctors pity him, his mother doesn't know what to do, and the rest of the town could care less.
Meanwhile, Frisk and Chara were way out of their comfort zone after a Reset gone wrong. To make matters worse, they woke up in the wrong body, in the wrong universe, and with weird flames flickering at their fingertips.
*Well, Chara's voice was just shy of malicious, at least you know how to dodge.
. . .
Warnings for the following: major character death (though I haven't really tagged it as such...), medical inaccuracies of epic proportions, possible Undertale inaccuracies as I have never played the game and gained my knowledge from posts, fics, comics and the Undertale wiki, nonbinary main character, Gamer AU, non-consensual body snatching.
If I have made an mistakes, feel free to correct me. I'll fix it up as soon as possible as long as it's an unintentional mistake.
As a fair note, this chapter starts approximately 2 years before the actual story line, so Tsuna is ten going on eleven
I have also elected not to put this in the crossover category because the only characters from Undertale that will appear in The Game Changer are Frisk and Chara. And I don't really see it as a crossover. This fic mainly started due to my love of the Undertale Game Mechanics which are unique and easy to experiment with. I've wanted to do a Gamer AU for a while now but I've never had the courage since I'm not aware of how most games work with their ATK, DEF, and etcetera. Undertale's Game Mechanics, however, are simple to use and easy to experiment with. Hence why I've chosen to stick Frisk and Chara in Tsuna's body, and if you want to think of this as a crossover then, let's say, think of the two time-travelling children as Tsuna's 'alters'.
. . .
"Tsu-kun…" The woman's eyes were wide and earnest, filled with hope and similar warm emotions. A lesser being would've folded like wet paper.
But Frisk had never been anything less than what they were, so they simply clenched their jaw and held their head high. An inkling of uncertainty almost made them falter, but they were nothing if not determined. They've faced Asriel at his best, they've faced Sans at his worst. A simple human woman was not going to scare them into submission.
She. Was. Not.
"I've told you before, my name is Frisk… I'm not Tsuna."
The woman's – Nana's – eyes started to glisten. Frisk tried not to feel guilty, but it wasn't easy to resist those eyes. Especially when one considered the situation both of them found themselves in.
*She's pretty dense, isn't she? Frisk's eyebrow twitched at the voice of a certain demonic cockroach. For a moment they thought they that if they pretended hard enough, the ghostly child would fade from existence. A part of them was relieved they weren't in this alone but another despaired at being stuck with Chara of all people.
Out of the corner of their eyes they could see the being leaning over their shoulder, a curiosity usually seen in psychopaths and children shining through their perpetual smile. Frisk shivered.
"B-But…" Nana trailed off, looking more like a lost child than a mother. "You are. You are my Tsu-kun. I can recognise my own son when he's staring me right in the face!" Her voice had risen as she finished, chest heaving with frustration.
*Obviously, she can't. They ignored Chara's snicker.
Frisk themself was feeling pretty frustrated at this point. They've been doing this for the past fifteen minutes ever since their doctor had left to consult with a colleague, with Frisk insisting they're not who these humans think they are and Nana insisting they were her son.
Ha! As if they would ever defer to something as pointless as gender.
"Well, maybe you need your eyes checked!" Frisk snapped, Chara's voice grating on their nerves, not to mention Nana's expression just plain out pissing them off. They'd tried to be patient, but clearly that approach wasn't working. "My name is Frisk, and I'm not a boy. I'm not a girl either. I'm just me, so please refer to me as such."
Nana looked so horribly confused it would've been pitiful, but right now it was just infuriating.
After everything that's happened… Frisk wasn't in the mood for pity, or compassion, or offers of friendship. They were tired, exasperated, and more confused than that first time a Reset malfunctioned and they ended up in a warped Underground that was more edgy than a teenager in the peak of puberty.
To make matters worse, they barely remembered how they ended up in this body. They remembered the Lab, chatting with Alphys, Flowey popping in to throw his scheduled temper tantum, and then… Void.
Their little shit of a soulless brother pushed them into the Void. And Frisk didn't know whether it was on accident or… not. They didn't know which one would be worse.
Either way, they were less than pleased with their current situation. And that was before they woke up in the body of a supposedly comatose 10 year old.
Seeing as they've only experienced the female body to these extents, they were definitely thrown off and more than a little uncomfortable. Dear Stars, after years of hating their body you'd think they would appreciate a new one. But no, of course not, because having something between their legs was a hundred times more uncomfortable than having a… well.
They had woken up in a hospital bed and, after having the appropriate panic attack once realising they were Aboveground, looked at the board at the bottom of the bed to see what was going on.
According to the information they gleamed from the papers (which honestly wasn't much, they had never been all that good at written Japanese), they accidentally stole the body of one Sawada Tsunayoshi. His mother was Sawada Nana while his father was a suspiciously missing Sawada Iemitsu. He'd landed in the hospital after being pushed down a flight of stairs at school.
And, according to the doctor, he had no hope of ever waking up. Too much brain damage, too little brain activity. He was declared brain dead after two hours but put on life support at his desperate mother's request. No one expected him to ever wake up.
But he did.
Except he didn't.
Because Frisk (and by consequence, Chara) did.
Tsuna didn't.
They were declared a 'modern day miracle'.
Frisk sighed at the memory of the hospital staff flocking to their room, wanting to catch sight of the apparent 'miracle child'.
In case you were wondering, they weren't. A miracle child, that is. They simply had good time management, horrible luck, and an ungodly amount of DETERMINATION.
The door slammed open.
*Son of a—
"Language," the immediately disapproved.
Good manners had been beaten into them at a young age; proper language being one of them. Of course, they rarely used them but they weren't going to allow Chara (who was physically their junior) to swear. Let alone in public. Nevermind that nobody could see them. They could. They would know. They already had enough weighing on their conscience to deal with Chara and their foul mouth.
"What?" The doctor from before had returned, this time with another one of his kind.
"Don't mind me, sensei. I was speaking to Chara." They deadpanned.
They had nothing to lose. He had already seen them scolding the demonic ghost on how to be a proper sibling and for stars' sake do not call you brother that ridiculous word. There was literally nothing worse they could do in his eyes, sans declaring to take over the world with the power of magic, video games and homicidal children.
Their eyes were drawn to the second person, who slowly slid into the room like a predator assessing his surroundings.
The new doctor sharply contrasted the first one. While the first had light hair and dark eyes, his hair was much darker and his eyes were silver, hidden behind glasses. When Frisk squinted and tilted their head at the right angle, he reminded them more of a model than a doctor. The only thing that ruined his pretty boy image was his unkept hair, his preppy outfit and the weariness in his eyes. He looked like he needed a week of uninterrupted sleep and a timeline's supply of caffeine.
*Wow. Just wow. I think that if I tried hard enough, I could fit myself into those eye bags. Chara sounded almost impressed with his sleep deprivation.
"Chara?" The new doctor piqued in. His stare, which was unfortunately directed at them, was unnerving Frisk. It reminded them of how a cat stared at a particularly interesting mouse, or how Sans stared at them after their first LOAD.
They hesitated, "Chara… is someone who's always been with me. I doubt you'd want to meet them. They're a bit…" how should one go about describing Chara while omitting all the genocide and all round terrible personality? "Rude."
*Screw you! I'm not rude, you're rude! Chara's smile turned into a barring of teeth.
"Hmm," doctor numero dos sounded unconvinced.
"Um," Nana tilted her head, a brittle smile attached to her lips. "And who might you be?"
"I'm the head of Namimori Hospital's Psychology Department, Kobayashi Kiyotaka. Call me 'Kobayashi-sensei'," he eyed Nana for a second before dismissing her as unimportant. His cold, cold, cold eyes stare directly into Frisk's befuddled ones. "The attending doctor called me in to do an assessment on your son, but from what he's told me, it's obvious what's wrong with him."
"They," Frisk muttered. They had a feeling that pissing this Kobayashi off would come back to bite them in the butt later…
"Pardon?"
"Please use they/them pronouns when referring to me. And my name's Frisk, not Tsunayoshi, not Sawada, but Frisk." They hoped that at least one person in this room had enough brains to respect their wishes.
An eyebrow rose but other than that, Kobayashi gave nothing away that would indicate his surprise. "I see…"
"You know what's wrong with Tsu-kun?" Nana's eyes once again filled with tears. Frisk needed to know where the water kept coming from – they thought she had run out half an hour ago!
"Obviously," Kobayashi drawled.
His tone didn't so much as make her falter. "Please tell me!"
He sighed, "I was just about to do so."
*I don't know why, but he pisses me off. Chara squinted at him. Can I—
"No," Frisk immediately shot that idea down.
"No?" There was an edge to Kobayashi's voice. Frisk tried not to shudder.
"S-Sorry, I was talking to Chara…" They avoided looking him in the eye.
"Hm," he hummed.
Idly, Frisk wondered how high his LV was. The whole atmosphere of the room changed as soon as he entered, which normally indicated that the person had a thirst for blood, death and mayhem. Or… that they've killed before.
"Kobayashi-sama…" Their attending doctor shifted nervously.
*'Sama'? Is that a normal term of address in this godforsaken country? The demonic ghost questioned, but Frisk didn't reply.
It wasn't an honorific used when referring to a doctor, not even a department head. That was suspicious to say the least…
Their eyes narrowed for a split second before returning to their usual half-lidded state. Then again, it's been a while since they've spoken Japanese, let alone visited the country. For all they knew, Kobayashi could've owned the hospital or something as ridiculous as that.
Either way, it was none of their business.
"I was getting to that," a thread of annoyance entered his voice.
Doctor numero uno edged away from him, seconds away from booking it. Frisk wanted to join.
Kobayashi turned back to the body snatcher and began, "Frisk, how old are you?"
That was an odd question to pose, especially to 'Sawada Tsunayoshi'.
They could see Nana opening her mouth to answer out of the corner of their eyes, but interrupted her before she could start. "I'm 12, though I often feel older." Especially when one took into account the numerous Resets and LOADs…
"Nationality?"
"I was born in America, but one of my parents was Japanese."
"Parents? Siblings?"
"My mom's Toriel, I don't really have a dad. I do have a dunkle though, Sans, and he has a brother, Papyrus. I have a brother, Asriel, and… a sibling, Chara."
*Take that back! As if I would ever want to be related to you, idiot! They ignored the fuming ghost with practiced ease.
"Is Chara here right now?"
"Yes, they're always with me."
"And how old are they?"
"Ten or eleven. I'm not sure."
"Why not? They're your sibling, aren't they?"
A shrug, "I guess. But they're a bit of a jerk so I don't really pay attention to them most of the time. Besides, they've been the same age for a very long time…"
"And why is that?"
"… I don't want to talk about it."
"Hm," Kobayashi leaned back a little. He's taken a step closer every time a question left his mouth, now standing right next to the bed.
Frisk shifted away, uncomfortable with his aura. They've gotten pretty good at CHECK over the past few timelines (stars knew they had to, with every timeline being weirder and more unpredictable than the last) and since their instincts were screaming at them to put as much space between them as possible…
The last time they ignored their instincts, edgy Papyrus killed them during their 'date'.
"I was correct," Kobayashi nodded his head. "You," he poked their forehead with a finger, "have Multiple Personality Disorder."
"Eh?"
"What?"
*Holy shit! Chara guffawed, doubled over holding their stomach. I mean, it's not like he's wrong! I am sorta like a split personality, ain't I, partner? Their grin turned malicious for a split second before falling into a glare. If we get thrown into a loony bin, I'm killing you myself.
That was fair.
"Multiple Personality Disorder?" Nana tilted her head. "What's that?"
How Kobayashi managed to look simultaneously annoyed and bored, Frisk would never know. They feared for the woman's life.
Stars, they sure hoped their CHECK was malfunctioning.
The other doctor jumped in before anything could happen. "I-It's a mental illness characterised by having two or more personalities, or 'alters'. They often have their own names, ages, genders, personalities, and even warped memories. Tsunayoshi-kun's alters are Frisk and Chara. It often happens after a traumatic experience. I'm just frankly amazed Tsunayoshi-kun woke up after such a hit to the head," the doctor shook his head in disbelief and awe.
"No," Kobayashi spoke up, never once taking his eyes off Frisk during the whole explanation. "Tsunayoshi didn't wake up."
"But sensei, he's sitting right there!" Whatever Nana wanted to say next, she didn't, because Kobayashi shot her a brief stare (not even a glare, he was just that intimidating). Even she was smart enough not to get on the psychologist's bad side.
"No, he isn't," he said simply. "That's Frisk, Tsunayoshi's alter."
While they were offended at being called a mere alter, they didn't voice it out loud. In the long run, maybe it would be better if they pretended to be a split personality instead of a time-and-space travelling human child. They wouldn't even know how to breach the whole 'body stealing' subject, let alone know if the doctors would believe them. At worst, they would definitely be thrown into a mental institution.
"Then where's my Tsu-kun?" Nana demanded tearfully.
"I wonder," he tilted his head, glasses flashing ominously in the light, "where is he, Frisk?"
Suddenly, all attention was on them.
Frisk tensed.
That… was actually a good question. They frowned. While they weren't the best at medicine and injuries, they knew enough to realise that the fall Tsuna took would've killed a normal person. Or, in this case, caused enough damage to declare him brain dead with no hope of ever recovering.
After having been possessed by Chara during the later parts of a Genocide Run, they had enough experience to determine if there was a second party in their psyche.
But when Frisk closed their eyes and tried to look for even a flicker of a SOUL, there was nothing except their own shining DETERMINATION and… a thick, cracked wall with orange light filtering through.
Eyebrows furrowing in bemusement, they tried to focus on the semi-ruined wall to see if Tsunayoshi was around. The only thing they felt was drowsiness coming from behind it, and not the type that belonged to a human.
They mentally shrugged, noting to investigate the wall much later in their residency.
Either way… there was no Sawada Tsunayoshi anywhere they looked. A glance at Chara told them the same thing; the boy wasn't in their psyche either.
Sawada Tsunayoshi, 10 years old, and already dead.
What a sad life indeed.
They look back at Kobayashi, whose minute slump of shoulders was almost unnoticeable.
"How unfortunate," he muttered.
"What's unfortunate?" Nana peered up at him.
"Your son is dead. Maybe the brain damage killed him and his alters took over in his stead. I don't know," he sighed.
The mother's face crumpled as a loud sob escaped her throat.
Frisk cringed. That sob… reminded them of Toriel in the worst of ways.
Chara must've felt the same because they scowled at the woman and pointedly turned away from her, covering their ears. Childish, but effective. It's a shame Frisk couldn't follow by doing the same. It would be morally wrong.
The first doctor panicked, hurriedly trying to reassure the woman.
"B-But there's a little bit of Tsunayoshi-kun left in, uh, Frisk too!" His voice pitched higher as the eyes of everyone turned to look at him, "I-I mean an absentee dad, a mom h-they obviously love… It reminds you of yourself, doesn't it? Frisk could've, uh, modelled Toriel after you! I don't know where Sans and Papyrus come in, b-but they could be modelled after some adults in their life! And maybe Asriel is modelled after a friend…? Chara is another alter, isn't she?" He turned his hopeful eyes onto the bemused and slightly offended child.
"They," Frisk muttered absentmindedly.
They were not an alter! They had their own name and memories and family for stars' sake! But they couldn't deny that pretending to be one was the best course of action right now.
"See?" The doctor turned back towards the hopeful woman. "This… Frisk is still your Tsu-kun, just… imagine them with amnesia! Frisk is still your child, and so is Chara, you just need to make new memories! They'll see you as their mother in no time!"
Frisk bit their cheek to hold back a less than pleasant retort. As if they would ever see a human as a parent ever again. Their last human parent was less than pleasant and was the sole reason they even climbed up that godforsaken mountain in the first place. The only person they would ever view in a parental light was Toriel. She was a good mother despite all her faults (i.e. attempting to kill them).
Kobayashi didn't look convinced. He rather looked like he doubted the man's sanity, or rather his resolve. After all, what sort of doctor crumbled at the first sign of tears? Or maybe he doubted that Frisk would ever see Nana as a mother? Who knows, he was a psychologist. They're notoriously tricky.
"Oi," Frisk had no idea whatsoever that a single word could sound so threatening—
The rambling doctor froze at the steely intonation and wisely shut his mouth.
Satisfied, Kobayashi continued, "Frisk, do you have any inclination to harm others?"
With a straight face they replied, "No."
It wasn't a lie, per say.
Violence wasn't in Frisk's nature. They were a pacifist down to their SOUL. Unless you counted those times where the stress of multiple deaths, Resets and their inability to fully escape the Underground caused them to snap and go on a killing spree, after which they gave control over to Chara.
*Liar, liar pants on fire~ Chara sang with a sick grin imprinted on their face.
"And Chara?" The steeliness in his eyes implored them to tell the truth. Frisk wondered if he could tell they were lying. They… didn't want to find out, in all honesty.
And so, they told the truth, "Chara is… a violent person," their voice was low and collected, "But the only way they can hurt someone is if they po-take control of our body. And as long as I'm around, that isn't going to be possible. You see," a small smile appeared on their face, "my will is stronger than theirs, and my SOUL as great. They have no power over me."
They were a sucker for fantasy. Particularly the ones that involved travelling to another 'world' and making friends there.
Kobayashi raised an eyebrow at the botched quote but did not mention it.
Chara, however, did. *Oh screw you, partner! We both know that's a lie! The countless genocides you committed prove it. They snarled.
Frisk ignored the temperamental child with practiced ease. You would think that after decades of experiencing the afterlife, they would call them down. Unfortunately, you would be wrong.
"So you're the 'gatekeeper'…" he tilted his head, "Humph, as long as you don't show any behaviour that could deem you dangerous, you'll be discharged within the week after some follow up tests," with that, he strolled out of the room as if he were never there. The door slid shut behind him silently.
Nana, the idiotic doctor and Frisk (with the unwanted ghost of Chara) stared at the closed door dumbly.
Frisk looked at the doctor, then Tsuna's mother, then Chara, and sighed.
. . .
Later that night found Frisk laying on their hospital bed with a pensive frown. Nana had long since left after the doctors had preformed some tests to find any lasting damage. They found nothing, thankfully.
The woman had promised to drop by tomorrow with some of Tsuna's old clothes and comics to 'make them more comfortable'. Her obvious attempts made Frisk sad. Tsuna was never going to return so they hoped the woman would give up on him soon. It would hurt everyone involved if she didn't.
A sigh escaped slipped from between their lips. Their forearms rested across their face, hiding their eyes from view. Their blankets were thrown askew as they found it to be too hot for them despite their thin hospital gown and the open window filtering the early autumn air in.
If they focussed hard enough, they could pretend they were back in Snowdin with Sans' snores coming from the living room and Papyrus making a mess in the kitchen. An involuntary smile slid onto their face at the memories of one of their numerous sleepovers, before it fell.
Frisk realised… deep down… that there were going to be no more sleepovers with the Skelebros. No more butterscotch-cinnamon pies cooked by their mom. No more cooking lessons with Undyne. No more anime marathons with Alphys. No more quizzes with Mettaton. No more tea parties with Asgore. No more fights with Flowey Asriel. No more Grillby's, Muffet's, Napstablook, the River person, Monster Kid, Monsters, alternate universes with edgy and genuinely murderous characters…
There would be no more Underground adventures for Frisk to complete.
They were stuck in a new universe with only Chara for company.
In spite of their greatest efforts, a strangled sob tore from their throat. They covered their mouth, wide tear-filled eyes staring at the ceiling.
They were all gone and Frisk was alone—
Another sob caught in their throat.
*… Frisk? Chara's uncertain voice made the tears flow harder.
Now, they wouldn't even be able to SAVE Chara and return them to their own body, however decomposed and skeletal it might be. Heh, the Skelebros would've loved having another Skeleton around, even if Sans had a history with them. He would've loved the kid after a few weeks of listening to them bitch and moan about chocolate and Asriel.
A small hand smoothed their new buzzcut like Toriel would do when they had a nightmare. Wide red eyes peeked at them from behind their bangs, uncomfortable and dearly wishing to be elsewhere. But Chara steeled themselves and squared their shoulders.
*It's going to be—
"It isn't," they shot down Chara's attempt at reassurance.
*Yeah, it isn't… Chara acquiesced, But you still have me. It's not much and I know you'd rather have anyone else, hell, even Flowey in all his soulless glory would be a better choice. But we're partners, we're as thick as thieves, and we're going to get through this just like we got through the first AU. Together.
They rested their forehead against Frisk's, eyes softening in a rare moment of kindness.
"… Yeah," they croaked, "I'm not alone. Besides… who knows what this world holds for us. Maybe… Maybe there's a chance for us to return home…"
Chara smiled, but there was something akin to pity shining in their eyes.
. . .
Not much was known about the Void. The people who knew about it were even fewer than the information acquired about it.
The Void was an expanse of pure nothingness, as its name might imply. Unbeknownst to most, it had its own set of rules and laws and inhabitants. If a person fell in, they could not exit by any normal means. Usually, the abnormal means could not do much against the Void either.
However… the power that was linked to those with a tremendous amount of will and DETERMINATION… Reset… was one of the few powers that could affect the Void, for better or for worse.
Resets also had their own rules. Many were unknows and many more would never be discovered unless the right circumstances were met.
When a being capable of Resetting activates the power, they return to the beginning of their 'story', so to speak. Whether it was to change the outcome of the 'story' or just plain out destroy it, it was up to them.
But when Frisk (and Chara) fell into the Void, they soundly exited their 'story' and could never return. Their Reset was no longer linked to that particular universe.
It was then that the rules of the Void and the rules of Resets collided… and the Reset latched onto the wrong universe.
But since there wasn't a Frisk or a Chara in that particular universe, the Reset shoved them into the body of a person with a strong will. It was just a coincidence that the body belonged to the comatose and decidedly brain-dead Sawada Tsunayoshi, soon to be heir of the Vongola Famiglia.
What a peculiar coincidence indeed…
. . .
Anyone catch that botched "Labyrinth" quote? Eh?
Timeline:
1991: October 14 - birth of Sawada Tsunayoshi
2002: September 3 - Tsuna's had a great fall
September 24 - Chara and Frisk wake up
2004: first few events of KHR
I'm mainly using YazzyDream's timeline at the KHR wiki, with some altering.