Actions

Work Header

The Butterfly Effect

Summary:

Chaos Theory says that something as small as the flutter of a butterfly’s wing in Brazil can lead to a tornado in Texas. A clap of a hand can lead to a war. The death of a stranger could become your own.

A chance meeting might lead to salvation.

 

Or: my take on what would have happened if Geto and Yuji met before he died.

Notes:

To my lovely amazing friend Dame. Here's your (semi) healthy Geita bestie, ily.

Chapter 1: And So It Begins...

Notes:

Song for this chapter: snakelike (the stars collide) by whatsaheart

 

Spotify
Apple Music
YouTube

(See the end of the chapter for more notes.)

Chapter Text


The first thing Suguru thinks when the boy enters his temple hall is, Pretty.

His next thought is, What a pity he's a monkey.

Suguru has always been weak to lovely creatures—something Satoru had exploited beyond belief—and the boy in front of him is indeed lovely. Solidly built, an athlete no doubt, with a shock of pink hair too sandy to be anything but natural, and smooth, tanned skin. Wide brown eyes pin Suguru down with an alluring mix of expectation and skepticism. Despite the boy's apparent nervousness, he holds himself with the confidence of someone who knows that if he gets into a fight, he’ll surely win.

Yes, Suguru thinks again, it's a pity he's a monkey.

Suguru watches the boy approach his stage with an impassive expression and waits for him to speak. Today's batch of curse-collecting monkeys had been tedious, each more banal than the last. He figures he could indulge a little in the pretty thing before him, if only for a moment.

"Uh, excuse me, Mr. Buddhist Monk, sir. I heard you can, um, heal people?" Amusement courses through Suguru's veins. Perhaps this boy is more nervous than he's letting on.

"I have been known to do that," Suguru nods. "Are you in need of healing?" He doesn't see any curses attached to the boy, so it must be a sickness or physical ailment.

"No, um, not me. My grandfather is really sick. Lung cancer. Is that something you can help with?"

Ah. A sickness, then. Unfortunately for the boy nervously fidgeting in front of him, there is nothing Suguru can do about cancer. Many years ago, Shoko hypothesized that Reverse Cursed Technique could potentially be used to treat the effects of cancer and restore mutated cells to their proper functions. Ultimately, she decided that although it could work in theory, it simply wasn't possible to maintain[1]. Even if Reverse Cursed Technique could be used to treat cancerous cells, Suguru has never been able to master it on himself, much less on anyone else. He certainly wouldn't waste that amount of energy on a dying monkey, anyway—even if his grandson is delightful.

Taking his silence for rejection, the boy starts rambling.

"I, uh, had a super hard time finding you. A lot of it is from word of mouth, y'know, so I don't know if you need compensation or anything. I don't have any money, but I'm really strong! Maybe I could do something for you in exchange—like a service for a service?"

Suguru is incredibly amused. He smiles indulgently and rests his chin on his hand. 

"I have many strong individuals amongst my team. What makes you think I would have any use for you?"

"I guarantee I'm stronger than any of them."

"Oh?"

The boy nods.

"I punched through a cement wall on accident once, and I broke the world record for shot put when I was a first year in high school. I also picked up a car on a dare, but I haven't tried that one again."

"My, what a little storyteller you are," Suguru purrs. 

"I'm not lying," the boy snaps. "I can prove it." There’s a tinge of offense in his voice. Suguru wonders if anyone has ever questioned his strength before.

"Fine then," he says, letting his amusement color his tone. "Destroy one of those." He mockingly gestures to the row of large decorative poles lining the temple hall. They're gaudy eyesores—left over from the previous occupants before Suguru disposed of them—but they're made of solid concrete. Destroying one without cursed energy should be impossible.

He expects to see a delicious red bloom across the boy's cheeks at being called on his bluff—perhaps some stuttered excuses or diverted eyes. Instead, the boy gives the pole a considering glance, undeterred, and asks, "Aren't those structural?"

Suguru says nothing, raising his eyebrows in expectation. The boy takes his silence in stride and calmly walks toward the nearest pole. He stares at it for a second, takes a deep breath, pulls back his arm, and swings.

The pole explodes.

Suguru's eyes widen in disbelief. No fucking way.

Immediately, his attention narrows on the boy, scanning his body from head to toe. He half expects to see blood splattered across the ground, or the boy struggling to breathe with a shattered arm. Instead, he sees a beautiful anomaly waving his hand to clear the dust from the air. Save for the occasional cough, he is completely unharmed.

Suguru is openly staring now. He didn't even split his knuckles. That shouldn't have been fucking possible. He didn't detect a single flare of cursed energy, yet the pole was destroyed in a plume of dust.

There's no way a non-sorcerer could do that much damage without shattering every bone in their arm. Not unless —he stops short in realization. Unless…

The boy is rambling at him now, something about not knowing the pole would explode like that, but Suguru ignores him. When he first entered the hall, Suguru had assumed the boy was a standard monkey and hadn’t bothered to check his cursed energy levels. He has reason to check now.

Slowly, he lets the tight coil of Perception loosen and permeate the room[2]. The feedback is instantaneous as it creeps across the floor toward its unsuspecting victim. Residual cursed energy from previously exorcized curses appears to him in soft, hazy waves of color. Finally, Perception makes contact with the boy, and Suguru sees him tense. A long time ago, Shoko had told him that getting caught under Perception felt like her entire body was blanketed in pins and needles. 

“Like when your foot falls asleep and slowly regains sensation but it’s your whole body,” she had said, “Distinctly unpleasant, but not painful.”  

Suguru knows the boy must feel that uncomfortable static across his skin, but he can’t bring himself to stop his investigation. The boy’s cursed energy is something of a marvel—light blue, so bright it’s practically glowing, and large enough to fill his entire chest cavity. Sorcerer material, Suguru decides, as he watches the blue ball of light writhe and stretch under the stimulus of Perception. 

Unfiltered rage fills Suguru’s chest as he realizes what has happened. Someone had taken this beautiful creature when he was a baby and ruined him, severing him from his very birthright of Jujutsu. There, blanketing the boy’s cursed energy in a vile red net, is Suguru’s suspicions made reality. 

A heavenly restriction.

He had seen something similar many years ago when he and Satoru had fought the Sorcerer Killer. The color was the same—pulsing, violent red, settled snugly over the ball of cursed energy in the assassin’s chest. Toji Fushiguro’s cursed energy wasn’t impressive—a sort of dusty purple and roughly the size of a watermelon—but the heavenly restriction had allowed him almost unnatural speed and frightening strength. It made him deadly.

Suguru takes pity on his unwilling captive and condenses Perception into his chest. He watches with gluttonous contemplation as his newfound treasure gasps and readjusts to being the only person under his skin.

Years ago, when he was still a student at the Jujutsu Technical College, there had been theories—or rather, wild speculations—that heavenly restrictions could be removed. Suguru had never paid attention to such rumors. He was too worried about Satoru’s behavior and, later, his slow descent from Jujutsu society. Now he wishes he had given those rumors a second thought.

If he could find a way to remove the heavenly restriction, to break the chains and free one of the most potent cursed energies he’s ever seen, this boy could be monumental to his cause. He feels almost giddy at the thought.

A strangled question snaps him from his reverie.

“What the fuck did you just do?”

Suguru molds his expression into apologetic concern and makes his way over to the still-shaking boy. “Apologies for that. Your display of strength was enlightening, and I merely had to confirm something. I’ve been told that little test of mine is unpleasant. Are you alright?”

The boy stares at him wearily, his guard raised high, before nodding. 

“I’m fine. How did you do that? What were you testing for?”

“I will answer all questions in time,” Suguru coos. “Now, please, tell me your name.”

“Oh, it’s Itadori. Itadori Yuji.”

Yuji.  

The name curls around Suguru’s mind like a warm embrace—a lovely name for an equally lovely boy, and so very fitting[3]. Suguru has never believed in fate, not really, but surely this is a sign. 

“Itadori, I don’t think there is much I can do for you regarding your grandfather’s lung cancer,” His mouth twitches in amusement when Yuji droops in near-tangible disappointment, “But I believe I will be able to ease his suffering. Would that be sufficient?”

Yuji’s head shoots up to look him in the eye, a spark of hope flickering across his face.

“Yes! That’s totally sufficient!”

“Perfect.” Suguru reaches into the sleeve of his yukata and retrieves his phone. “I’ll arrange a car to take us to your grandfather.”

“Oh, no need sir, I—” 

“Geto.”

Yuji blinks in confusion.

“What?”

“My name. ‘Sir’ is so formal, and we’re familiar now, aren’t we? Please, call me by my name.”

“Familiar, right.” Yuji nods slowly. “Well, like I said, there’s no need to call a car for me. I rode my bike here.”

“Nonsense, your bike will fit in the trunk.” Suguru raises a hand to quiet half-hearted protests. There’s no way he’ll let Yuji out of his sight now. “Besides, I’ve already called it. Now, tell me about your grandfather.”

 


 

The picture Yuji had painted of his grandfather in the car is a far cry from the man sleeping in the hospital bed. Itadori Wasuke had been described to Suguru as a somewhat formidable man—grouchy, strong-willed, and possessing very little tolerance for foolishness. 

“Gramps is the definition of tough love, but he really does care for me,” Yuji had muttered in the car, looking out the window. Suguru doesn’t understand why anyone would go out of their way to seek healing for a man who seems so unpleasant—and a monkey no less—but he has no reason to complain.  

The man before him holds none of the vitality he once boasted. The cancer has ravaged his body, stripping him of his muscle mass and vigor, if the sunken cheeks are any indication, leaving him small and frail. Suguru wasn’t lying when he said there was nothing he could do to treat the old man’s cancer. That truly is outside of his realm of power. However, there is something he can do. 

Perched squarely on Itadori’s chest is a small, gargoyle-esque curse. It’s an ugly little thing—withered brown with teeth far too large for its mouth—but it’s almost harmless. The little cretin has been feeding off the sickness and despair permeating the room. Suguru wouldn’t be surprised if it had formed from the old monkey himself rather than being a standard hospital curse.

He sizes up the curse to judge how much it will fight Collection. Suguru has no plans for consumption—the puny curse is hardly worth his attention—but exorcism would be overkill and might harm Itadori. Not that he cares if the monkey dies, but he’s smart enough to know that accidentally killing Yuji’s grandfather would do him no favors in convincing his enigma to stay with him.

Suguru reaches a hand toward the curse and lets Cursed Spirit Manipulation flood his system. He senses the familiar tugging sensation of his technique attaching to the curse and pulls. Immediately, the curse shrieks and claws at the air as it begins to condense into a ball. The effort is futile. In the blink of an eye, the measly thing is reduced to a smooth black orb, small enough to fit in the palm of his hand.

“Aw, Geto what the hell! You killed Jerry!”

What?

Bewildered, Suguru turns around to stare at Yuji.

“I killed… Jerry?”

“Yeah, Jerry! You know, the little guy you just turned into a marble? What did he even do to you? He was just sitting there!”

So he can see them. Good.

“You named the cursed spirit that was draining your grandfather’s energy Jerry,” Suguru drawls, unimpressed.

Yuji shifts uncomfortably, and to Suguru’s internal delight, a small blush of embarrassment colors his cheeks. “Well, yeah. I mean, he just showed up one day and never left, so I named him. He just kinda sat around and slept on Gra—wait, what do you mean by draining his energy? Jerry was hurting Gramps?”

“No,” Suguru sighs, tucking the curse into his yukata. “It wasn’t directly hurting your grandfather. It was, however, making his life more difficult. I wouldn’t be surprised if the curse made his symptoms much worse than they should have been.”

“Oh. Well, I guess it’s probably a good thing you killed Jerry then.” Yuji glances back at his grandfather’s sleeping form—his breathing already beginning to stabilize—before speaking again.

“Can you teach me how to do that? Kill curses?”

Yes, Suguru thinks as he stares into wide, hopeful eyes, I’ll teach you anything you want to know. 

“It will be challenging,” he says, “more than anything you’ve ever done. Are you sure you want to learn?”

Yuji nods vigorously. “Yes! Please teach me to exorcise cursed spirits!”

Satisfaction floods Suguru’s chest at the display of blind enthusiasm. Once he figures out how to break the heavenly restriction, his boy will be magnificent. 

 


 

After making formal plans to meet the following week, Suguru leaves the hospital with newfound vigor. Breaking Yuji’s heavenly restriction will take time, but he plans to use that time wisely. His lovely naive boy agreed to “start slow” and work with Suguru on martial arts before they could begin exorcisms. While it is true that Yuji should become proficient in combat before attempting to exorcise a curse, the real reason is to buy Suguru time. He doesn’t know where to start looking for information on heavenly restrictions, and, unfortunately for him, getting information involves asking questions. 

Having a “kill on sight” order on your head doesn’t exactly encourage research.

There’s only one person Suguru can call who might have information and wouldn’t immediately turn him in. Humming, he scrolls through his contacts. They haven’t spoken in almost three years, skirting around each other in the world’s worst game of cat and mouse, but Suguru knows they’ll answer his call.

He taps on their name and brings the phone to his ear. The outgoing tone rings once… twice… three times before it finally connects. 

...Suguru?

A malicious smile creeps onto his face.

“Hello, Satoru.”

Notes:

1. Buckle up kiddies, it's a crash course on cancer. We all know (I assume) that cancer is the uncontrolled division of cells in the body that eventually become abnormal and dangerous. Cancer starts from a mutation in one of three genes: tumor suppressor genes, proto-oncogenes, and repair genes.

Tumor suppressor genes prevent cell division from happening too fast. A mutation in this gene could cause a “loss of function” mutation, and there would be no checks on cell division. Proto-oncogenes (where the term oncology comes from, by the way) promote cell division. A mutation on these genes might cause a “gain of function” mutation, meaning it would begin to divide cells way faster than it’s supposed to. Mutations in repair genes are also “loss of function” and prevent the genes from repairing the above mutations.

Now onto how Reverse Cursed Technique fits into all of this. There’s not a whole lot of information on RCT since not many people can do it, but what we do know is that it only allows for growth/regeneration and can’t destroy anything by nature. Theoretically, you could use RCT to essentially restore the mutated genes into properly functioning, non-mutated forms. But how would you do that? Without getting into the nitty-gritty of it, sometimes mutations involve extra DNA bases added to the code. To restore the gene to proper function, would you have to destroy those extra bases? That goes against RCT’s innate function. What about the concept of regeneration itself? We know that RCT can grow back limbs, which suggests that it’s creating DNA. But is it creating new DNA, or is it copying existing DNA and then your brain takes over and turns on the correct proteins to make that DNA function as, let's say, a hand? If the latter is the case, what’s to say that it’s not just copying all of the cancerous DNA and spreading it everywhere? Would you just have to wipe clean and regenerate every single cell in your body? There are wayyy too many moving parts in both cancer and RCT, and we don’t know very much about either of them (I’m also not an oncologist, so my understanding is limited to my current education).

In the end, I (and the friends who helped me brainstorm this) decided on RCT being unable to effectively treat cancer, at least long term. Perhaps a sorcerer could constantly use RCT on themselves to revert the mutating cells, but it could very well end up as a Mechamaru-type situation where they would be stranded by their own cursed energy and the effort it would take to constantly use RCT. It just wouldn’t be feasible to do outside of theoretics and technicality.[ back to text]

 

2. I have this headcanon that because Geto’s technique involves him swallowing cursed spirits (ie. concentrated cursed energy), he is then able to essentially “see” the cursed energy of other beings. My thought is that he uses this ability to identify sorcerers from non-sorcerers, as well as accurately grade sorcerer/curse levels. My friend took it a step further and suggested that he can choose whether or not to use it and it works like echolocation (which made me laugh really hard). I liked that idea, and thus Perception was born.[ back to text]

 

3. Like all Japanese names, the name “Yuji” has several different meanings attached to it depending on the kanji used to write it. If my research is correct (I don’t speak Japanese, nor can I read kanji, so I’m working based on internet translations) the way our Yuji’s name is written (悠仁) translates to something close to the overall meanings of “calm, permanence, compassion, and humanity”. Now, Gege said that he picked the name randomly, but I think he couldn’t have picked a better one.

While the meaning behind Yuji’s name sounds kind of the opposite of what Geto’s crusade is going for, I think there is a way to twist the meaning a little bit. Humans are really good at shoving things into boxes to fit our narrative, especially when we’re devoted to an idea. Thus, I don’t think it’s out of line for Geto to hear, essentially, 'permanence' and 'humanity' and immediately go “Oh, this is for me.”

If we all remember, Geto doesn’t consider non-sorcerers to be human. His goal is to wipe them out (okay Hitler, jeez), so for this potentially overpowered boy to show up bearing a name that suggests permanence for humanity, what's to say to Geto that it’s not his humanity, y’know?[ back to text]