Chapter Text
‘It has been estimated that approximately 14% of the population do not have a soulmate.’
Which is more than the amount of left-handed people in the world. Senku had read this in a journal once, and doubted the accuracy ever since. But it’s accuracy didn’t really matter since most of the world deemed it as fact.
It could be fun to think about, sure. People are drawn to these absolute numbers and accept them as truth, even the completely false ‘humans only use 10% of their brains,’ which became widely quoted and popular as well. (Though now debunked.)
Senku thoroughly disliked how facts like these ran with the majority of the population. After that number was estimated in 2002, it was popularized just a few years later, colloquially referred to as The Lonely 14% which implies some sort of deficit in the lives of the ‘unpaired.’
There was a lot that went into getting that number, census data from multiple countries, countless surveys over a time period of 8 years of collected data. Not that anyone cared that the researchers themselves made note that despite all the work, that numbers could still be inaccurate. It didn’t matter, the term soulmates came up very often, used near-interchangeably with partner and significant other.
It’s basically a given that a large gathered census from nearly every country is bound to be inaccurate. The thing that stuck in peoples heads isn’t that this could be incorrect, just the easy part to remember. That’s what always got the masses.
The Lonely 14%.
Roughly, 1 in every 7 people.
There are worse odds for other things. The odds of any given person getting cancer in their lifetime is one in four. At least now in the 21st century.
Senku felt some type of way about the association that being unpaired somehow meant impaired. The immediate look of sympathy he got when he said he didn’t have a soulmate. The direct probing afterward went like this,
“How do you know?”
“Are you sure?”
“The connection may be unique, maybe you haven’t figured yours out!”
Ever since Senku was 9 years old, he was near-certain of this fact.
Now a scientist, Senku knew it was arrogant to believe in absolutes when there’s always a chance to be proven otherwise. But he’s had years to be proven wrong and to this day he hasn’t. Which doesn’t impair him at all.
It’s not like he was mourning not having a partner, everyone else did that enough for him.
He did his research, a long time ago, and none of the hallmark pulls were there for him.
It wasn’t even a month after Taiju had met Yuzuriha. Senku had become slightly fixated on the research compiled about soulmate bonds, the different nexuses that manifest. Most are physical, but the second type emotional was less understood.
A Physical Nexus is easily measured and thus easily recorded. These types came in the form of names on skin, birthdates, matching symbols, or even feeling each others’ pain which would manifest in mirror bruises. (This Senku found incredibly interesting in fact, but he had never met a person who displayed this type.)
Matching symbols was by far the most common, there were even forums online where you could find your ‘other half’ via this method. Not that Senku’s ever bothered to look knowing it wouldn’t be of any use to him.
His best friend Taiju was part of the lucky minority who met his soulmate before the age of ten. Senku knew Taiju a year before he met Yuzuriha and believed his colorblindness to just be natural. One afternoon, he met Yuzuriha and his red-green colorblindness, deuteranopia was gone. He could suddenly see the full spectrum.
Taiju was nine years old when he nearly tackled Senku in the park, too excited to tell his friend the great news. Instead of capturing Senku in an unwilling hug, Senku sidestepped him, and Taiju fell on the ground face-first. That didn’t bother him at all, he got up, grass in his hair, smudging dirt away with the back of his hand just glowing.
“Senku!!!” Taiju yells out, “I can see!”
“Is that any different than yesterday?” Senku asks, “You—”
Senku was completely interrupted by Taiju’s excitement, his friend put both hands on his shoulders in a strong grip. He probably wasn’t even conscious of it.
“Woah!! Senku, you said your eyes were red, but they’re really red!”
Senku realized at that moment, their current assembling could be put off for another day–okay maybe an hour. His best friend could now actually see the color red. Identify its vibrancy as opposed to other colors. Senku was invigorated, he needed to know everything. Now.
“Taiju.” Senku says, somehow finding the energy to release himself from his friend’s grip, pulling his hand, directing Taiju to the blanket Byakuya had set up for them. (Even though Senku pointedly said this wasn’t a picnic.)
“We should talk.”
At the time, Senku knew about soulmates. The term was unavoidable. Literally every depiction of romance in media had them or mentioned them. People talked about marriage and if you weren’t sure that was your soulmate it was suggested that you reconsider, maybe even wait. It was always a subject of conversation among the older crowd.
He knew his old man had a soulmate out there, but he also knew Byakuya hadn’t found them. He had a tattoo of a star, five points, entirely black about the size of a 3cm square. It was high on the inner forearm below the wrist. He never made any attempt at concealing it, and always told someone when asked that it manifested when he was five, it wasn’t a tattoo. There was no removing a mark. Not even when a soulmate died.
Despite knowing about soulmates, Taiju meeting his was a complete surprise to Senku.
“I met my soulmate Senku! And she is amazing, she’s so—”
Senku is thinking while Taiju explains just how amazingly pretty and kind the girl he just met was. Yuzuriha, is her name. Apparently they met while inside of a store, and Taiju just stared for a moment because he couldn’t believe he saw everything when their eyes met. Then he ran to her and her mother like his life depended on it. (That last detail wasn’t said but Senku could make an educated guess)
Their parents allowed them to speak and they got icecream together. Taiju said he’s seeing her again on Sunday.
“She likes strawberry ice cream, she said it’s her favorite!!—”
Taiju continued to rant about innocuous details, and finished with,
“She goes to an all-girls school though so I will only get to see her on weekends Mom says.”
The fact that they were at the exact same store at the same time and met entirely by chance was such a crazy coincidence, Senku started wondering about how rare that actually was. What actually were the chances?
“So when you saw her, you could just see colors?”
Taiju nods, “Yeah!! But I didn’t know all their names at first.”
Taiju knows all the colors names, but of course it would take some adjusting to know which was actually which. He’s too energized so he talks some more,
“Pink is just a lighter red, and green is so much brighter now, but I think red is my favorite. Yuzuriha was wearing a red bow!”
Taiju was always so excited about anything, but this was an entirely new level. He was bursting at the seams with energy, with his eyes absolutely sparkling. Senku would be a liar if he said it was easy not to smile. He distracted himself a bit by taking things out of the wagon as Taiju spoke.
“She’s got…brown eyes and brown hair, she wore a white and pink dress, and a red bow, she likes Hello Kitty and…”
Some part of Senku knew he’d get a rambling session, so he begins to take his things out of his wagon as Taiju jumped up from the grass to spill every detail.
Senku’s memory was incredibly developed and he only needed to read something once to remember it. Hearing something was actually even better, he can recall tone of voice pretty well. He’d pretty much recognize Taiju anywhere.
After Taiju’s twenty minutes of talking about Yuzuriha—during Senku’s simultaneous wiring— Senku learned that Yuzuriha was in the prefecture visiting her grandmother. She went to an all-girls elementary school an hour away. Her birthday was March 31st, so she was an Aries, she liked jigsaw puzzles, board games, and she was learning to play piano and wanted to design dresses.
Senku heard Yuzuriha described as pretty and amazing, and cool, a total of five times, and he listens the entire way through.
“You’re seeing her again on Sunday?” He clarifies when Taiju takes a breath. Senku doesn’t look up.
“Mmhm,” Taiju affirms, Senku wishes he brought water. He knows Byakuya is here somewhere. He didn’t want to leave Senku by himself in a park despite how capable he is for a kid, but Senku doesn’t want to get up and ask for some. Byakuya is so overprotective of him.
“Ask her if she had colorblindness too.” He says, as he holds his model up to the sunlight to see if there are any imperfections. This was only the bottom half, and about a 1:12 scale. So it was going to be large.
He wants to know if this went both ways. Did she also have red-green colorblindness, or maybe it was entirely grayscale? He knew he would look more into soulmates when he got home, maybe ask Byakuya what he thought. Maybe.
“Okay!”
“And help me break apart this component Taiju. It’s messed up.”
“No problem Senku!”
*
Taiju was Senku’s only friend until middle school. Senku always just went to the school closest to where he lived, and Taiju lived close by too. Yuzuriha and her mother moved, and she transferred into their co-ed school. The three of them became close friends with surprising ease.
Before middle school, Senku only met Yuzuriha maybe four times. But when they were in the same classes now, Senku got to observe the two of them.
Seeing Taiju and Yuzuriha together by this point made Senku realize they’ve done a lot of talking during the years they didn’t go to school together. Yuzuriha could read Taiju like his thoughts were written in the air, and Senku could probably do so as well, but with more effort on his part. With her it came easily.
Yuzuriha was easy to get along with. She was empathetic, kind and when they first met she was kind of shy. Clearly Taiju had spoken of him. He won't forget that first meeting ever.
“Sorry Senku, I had a completely different version of you in my head.” At the end of the day, Yuzuriha said this and he only looked at her a bit inquistively. He was kind of used to people having the wrong impression of him. It didn’t matter. He wasn’t exactly cultivating interpersonal relationships here. Taiju practically strong-armed him into a friendship.
But Yuzuriha was insightful for her age, she had adept people skills intrinsically. She felt she had to say something even when nothing was wrong at all. She makes her feelings known. In a way she’s like Taiju, because he also wears his emotions proudly but she’s more thoughtful about when to convey them and when not to.
Senku couldn’t say the same for himself.
“You’re a good friend to Taiju, and when he said you make him help you with your work, I was expecting a tyrant or something…”
Senku makes a short sound close to a laugh, but not quite. Yuzuriha smiles, “I imagine you could be a tyrant with a team of workers around you. You’re pretty efficient.”
“I try to be. Efficient, that is.”
There’s only so much time in a human lifespan, after all.
That thought was strange, though not the first time he’s had it. The feeling of knowing you won’t actually be able to accomplish everything you want in a lifetime. But it hit him harder than it should have for the context of their conversation.
Sometimes Senku gets these feelings of melancholy, seemingly out of nowhere. Or feelings of doubt, or anxiety. It’s not the only reason he keeps his emotions close to his chest. It’s hard to invest in relationships with others when you can never really figure people out the way you would a set of numbers.
People were variables unaccounted for in any given scenario. Taiju was his best friend; he was easy to read and easier to be honest with. But meeting Yuzuriha probably set him on edge because he actually wanted to be liked by someone. He knew Taiju would put her first, and he should. But it was hard not to feel like if he did mess things up, it’d be his fault for not…knowing.
He can’t know everything, and he never will, and that fills him with an existential dread more than death ever will.
“I was curious, because Taiju had mentioned it in passing, but do you really not have a soulmate?”
It’s not weird for her to ask, people always want to help others find their soulmate. Especially those that have their own. It’s like something good happening to you and you want to share it with people you know or care about.
“I imagine Taiju and I aren’t enough to keep up with you.”
“You both will do just fine.” Senku says, forcing a smile, “Besides, now that I know you have crafting skills. I have ideas for you.”
Yuzuriha, like a true creative, beams, and it’s probably the most like Taiju she’s seemed in that entire day. But the feeling of dismissiveness didn’t go over her head. She didn’t bring up the idea of Senku having a soulmate again. He appreciates it. Senku realized then, that it wouldn't be hard to be friends with her at all.
*
The more Senku read about the emotional types, the more he felt like he was just reading psychology and the less he actually wanted to read it. But he did so anyway, because as always, he just wanted to understand. At some point, he felt like he understood enough and told Byakuya plain and simple:
“I’m basically 100% certain that I don’t have a soulmate.”
He was unbothered by it then, and Byakuya of course had no idea to say to his eccentric kid who brought this up with no prompting when they were eating breakfast.
“You don’t know that for certain.” He countered. To which Senku would think 'Who is the childish one here, when he speaks like that? ' Byakuya would answer, ‘It’s still you!’ He finds it useless to police this grown man's tone by now.
“Pretty sure I am, though. I read a lot.”
“I told you books aren’t the same as experience. Are you sure you feel that way?”
“Yeah,” He shrugs uncaring, “Can you pass me the salt?”
“Your eggs are salty enough.”
“Well I don’t think so.”
“See. Perception. I think I put too much salt, you think there isn’t enough.”
Senku didn’t think that was a good counter to what they were actually discussing at all. Byakuya passes the salt and pepper anyway. He wouldn’t tell Senku he had forgotten to season the eggs.
“And here, drink some water while you’re at it. You don’t drink nearly enough.”
Well that conversation was over. Senku didn't want to talk about the fact that sometimes he forgot to drink water. It's always around, he really should remember.
Back to the topic at hand, Senku didn't get the big deal about his declaration. There are worse odds for other things, it doesn’t mean Senku himself is particularly unlucky. He knows this. He’s content with it, but his father isn’t so sure of Senku’s nature. Deeming Senku irrational for declaring he didn’t have a soulmate at ten not too long after Taiju found his. Senku still had his entire life left to live and Byakuya worried Senku counted himself out too early and easily.
It’s Tuesday, Senku woke up from a thirty-minute nap and slogged himself to the kitchen. Well, he thinks it’s been thirty minutes, it might have been more. Actually, he's usually right about these things, so thirty minutes is probably exact.
Byakuya has been mostly talking to himself for the past two minutes, and Senku’s been half-listening as he went through the kitchen to find something both easy and mildly appealing to consume for energy. He was working on a document to send to Dr. Xeno by the end of the month. It was taking up a lot of his time. That and his prototyping.
So different streams wound in his mind at once. Despite that, it's easy for him to tune back into words being said to him.
“—Maybe you join one of those groups.”
Senku dryly laughs at that, as he opens the fridge looking for something to eat, as if there was anything he wanted. He checked two hours ago. He might just land on toast. Or asking his old man to make him an egg or two to have the leftover rice with.
(Not that he can’t make an egg or anything. He just really doesn’t feel like doing so, and he knows Byakuya is always happy to oblige him.)
“Yeah sure, I’ll join one of those soulless groups right away, old man.” He closes the fridge door in mild annoyance. He can easily keep up with Byakuya’s train of thought, to another person his statement came from nowhere. Byakuya only looks at him, like he hasn’t said anything of note at all. His eyes look at their small kitchen and sees the fact that Senku is in there at all. Senku’s clearly somewhat hungry considering he came out of his room for the first time in hours.
“Hey, you want me to order something?”
“Please.” Though it’s a requesting word in itself, it sounds like a plain statement from his mouth.
“Great.” Byakuya says, he’s always so chipper. “You’ll have to indulge me in conversation though. Which I know you hate.”
“I don’t hate it. You just come back to this more than occasionally and it kills the mood. You don’t have a soulmate either—“
“I have the connection to one.” He reminds like Senku could ever forget. “They’re just not with me now.”
“Right.” Senku replied, “You can be content with that, but you express complete denial when I tell you I don’t have one.”
“But you might—“
“Right.” Senku repeats. Tone only slightly different. “I might.”
“There’s many different ways a bond can be felt, so even your statistics or reports can’t be one-hundred percent.”
“I know they aren’t. Statistics aren’t always accurate anyway. They provide insight.”
“And I know it bothers you even more that the whole thing doesn’t make sense to you.”
“Because it doesn’t.” He mutters. Feeling like Byakuya is still talking to a wall here.
“But just like how scientists don’t know why we sleep—“
“To process memories, for energy for—“
“Right.” Byakuya says, acknowledging but interrupting. Smile on his face anyway. “I know, I know.”
Senku has long since crossed his arms over his chest. He’s kind of waiting for Byakuya to pick up the phone and order from one of the six places they always do. Sometimes he forgets his father was a retired astronaut. He’s undoubtedly a man of science, even now he is still a Professor but the man was such a romantic. A true believer in the non-scientific and someone who doesn’t try to pick apart things that don’t follow logic like Senku.
Meaning: Soulmates.
“As I was saying,” He sighs, “You can try, but not everything will make sense. Especially not people.”
“I’ve long since stopped trying to make sense of them.” Senku probably sounds bitter but it didn’t matter.
Byakuya’s expression seems to say, sure. But he continues without furthering it.
“I have to ask, in case you magically change your mind. But what do you want?”
“I haven’t considered it.”
“Never?”
Senku nods.
“Now are you ordering food? Or are you going to torture me with this discussion again?”
Senku knows he is a rather spoiled child. He never needs to push to get what he wants, and Byakuya is always happy to give whatever he wants to him. He knows that sympathy he got from being an orphan at like 4 really helped his case though. But Byakuya would have done the same anyway he was just like that.
With absolutely no pushing at all, he got to stay at home and still eat ramen from a restaurant anyway. Despite Byakuya saying takeout ramen isn’t as good. You should just get dressed and we can walk there.
Senku basically made it clear without any words at all that he’d rather just go in his room and nap his hunger off than change and walk for food at the moment.
“God you’re so lazy when it comes to basic necessities.”
Byakuya doesn’t ever mean this seriously. A lazy person wouldn’t be able to build a perfect 1:91 scale Saturn V. But maybe he means it a little bit, because why was his son like this?
“They aren’t as pressing.”
“You have executive dysfunction.”
“It’s not dysfunctional if it doesn’t inhibit my life.”
“It totally does. And you didn’t even dispute me.”
Senku only shrugged. Byakuya instead of ordering them Chinese dim sum like he initially suggested, had gotten them ramen instead without Senku pressing at all. He has a feel for what Senku wants to eat, and a very good read on those minute expressions of discontent.
Tonkatsu pork broth, of course. Byakuya didn't even need to ask. When they ordered delivery, it was separated from the noodles so they didn’t get soggy en route. He's still a firm believer that it's way better just to go.
“We should have just walked there.” Byakuya muttered bitterly when the food got there. “It’s kind of embarrassing to have the delivery guy come here to us.”
“It’s a twelve minute walk. Seventeen with how fast you are.” Senku says, because he just couldn't help but jab at his old man.
“Twenty five with how much of a drag you’re being about it.” Byakuya retorts childishly, to that, Senku laughs as he prepares his own bowl. They’ll have dishes, but he has his ramen from his second favorite place so it’s no matter really.
“How are Taiju and Yuzuriha doing?”
“They’re good.” Senku replies, more immersed in his food. But Byakuya loved to talk and eat. Well, he just loved to talk.
“Still dating?”
“Going on three years, officially anyway. And you haven’t forgotten that they are soulmates right?” Senku reminds him, with a tone unbefitting of a dependent and adult. His interactions with Byakuya were always like that.
“So you do believe in that stuff.”
“It’s not that I believe in everything regarding soulmates. Taiju and Yuzuriha are just an example. They’re kind of irrefutable evidence.” Obviously not every situation works if only one does. It’s like anything else.
“But you must, a little.”
“If I say yes, will that make you happy?”
“Exponentially,” Byakuya enunciated, taking out a side order of gyoza that was still in the takeout bag. Senku thinks it’s a little greedy. The ramen was plenty. He might still take a bite anyway, only if it’s still crispy.
“Of course I believe in it. Taiju was literally colorblind before he met Yuzuriha.”
“Oh right!!” Byakuya exclaims, with a smile clearly reminiscing. “You know, when he came over and you were doing…well whatever you were doing, and I saw him drawing. I kind of thought he was just really creative.”
Senku slightly smiles at his fathers 'nice' way of saying he thought Taiju was an idiot. He was, a little, even without the color blindness. Senku cared about him and Yuzuriha a lot so it never bothered him.
“Yeah I don’t remember that.”
“You’re always in your own head. It’d do you good to think more about others.”
“I only think about you, Taiju and Yuzuriha.”
“And two of them are more involved with each other than just you. When I bring up the soulmate thing, it’s mostly to mess with you. But you should really begin to make some friends other than them. You're going into college now, you won’t see them as much.”
He tries the gyoza, eating it and he knows he’ll leave the rest to Byakuya. They should have walked, but Senku wouldn’t admit that now.
“I’m fine by myself. You don’t have to worry about me, old man.”
“It’s my job.” Byakuya says, “There’s no way I won’t worry about you.”
A pause, Senku was 18, and had years long contact and discussion with an actual NASA scientist, was actually certifiably bilingual and still…He still was not fully comfortable with the fact he was a son. Which was strange, because he's been that longer than anything else. Not only that but it was probably the fact that Byakuya cares for him deeply and completely. Senku dimisses it it being apathetic, and even considering it somewhat cringeworthy (sometimes it is--) but it’s just always always been hard for him to voice his emotions unlike anything else.
Shouldn’t you be happy? That you have a father at all? Where would you be if not for him?
Senju pushes those thoughts away. Byakuya talks more and for some reason Senku finds the thought is not fleeting. It twists in his stomach until he forces himself to speak.
“How are finals going with your students?”
Byakuya looks up and with a sigh he says, “Let’s just say for one of my classes it’s going to be a generous curve.”
"If most of the class doesn't get something isn't that your fault?"
"It's Advanced Physics, it's not easy for anyone," Byakuya says, then he laughs under his breath, and looks at Senku with his ever-there smile, "Though, if you were in my class Senku, everyone would hate you.”
*
When presented with a question, you form a hypothesis. A potential theory or answer. If applicable, you gather data and form a conclusion. How one goes about gathering that data can vary, but in this instance, Senku’s data was gathered over years.
The day he spoke to Taiju, realizing how his friend’s connection manifested, made him want to research others.
Apparently the not seeing in colors thing usually is identified at 6 months of age. Yuzuriha’s parents had noticed, but Taiju’s apparently had not. Senku thought maybe their color blindness before wasn’t achromatopsia, but something with a little more leeway, in which Taiju couldn’t see certain colors on the spectrum from yellow to green. Senku didn’t meet Yuzuriha before she could see the full spectrum so he had no way of knowing without just asking her. She said,
“I couldn’t really see red that well? Since I see everything clearly now, it’s actually hard to remember how it used to be every day.”
An unreliable testimony, but Senku writes it down. As he does more thinking on this phenomenon, he finds that there are so many different documented accounts and books written on soulmates, and it’s own field of study. Recorded documents date back quite a while, but it went against what Senku knew about some things and he found it hard to wrap his head around it.
Not that he didn’t like a challenge. He just didn’t like things that didn’t make sense.
Like this metaphysical red string which was documented a total of 12 times and adored by pop culture and media. 2 cases recorded in China and a classic movie was even made about that couples’ story after they passed away. He spoke to Byakuya about all of this, and told Senku that he had a soulmate connection, in the form of a tattoo. Which was probably the most common if Senku had to guess. (He had later confirmed this to be right.)
“You need to get rid of your preconceived notions. I know you like to make sense of everything but no one could really tell you how it works or why. People just document their experiences in the chance it could help someone else figure theirs out. There’s usually nothing that hasn’t been documented before.”
“What if I don’t have anything?” Senku poses the question. Though he knew about soulmates his entire life, they felt like the stuff of a hypothetical future in which he wasn’t apart of.
He never thought something like this would reach him.
“It could mean you have an emotional connection instead, there were a few cases of pairings feeling pain even countries away to the same level.” Byakuya gives Senku the most basic example he can think of, though he knows it’s not something Senku can relate to, but it didn’t matter. Whether Senku had a soulmate or not wouldn’t change Byakuyas love for him. “If you don’t feel anything then perhaps you’re apart of those who walk freely.”
Byakuya’s words then were a very nice way of putting it.
Society had a general disdain for abnormalities. Not having a soulmate, having multiple, a severed connection, or an unreturned connection were all seen as tragedies or a failing on one’s moral character even. Not so dissimilar to the bias of more physically appealing people are seen as more trustworthy.
Not having a soulmate? Then that must be you then. Something must be wrong with you.
Perception has changed slightly, but there were still certain stigmas. Especially from country to country.
“And there’s nothing wrong with you if that’s the case Senku.” Byakuya ruffles his hair with a bright toothed smile, and Senku slides away from his hand after a moment. It felt condescending, but Byakuya was just like that. By this point Byakuya already knew Senku wasn’t a normal kid, and spoke to him more like an adult than a child, but that didn’t stop him from seeing Senku as one. (Case in point, the physical affection he gave to him so freely.)
Much to Senku’s constant annoyance. He knows he’s a child, he doesn’t need to be reminded. He’s just never felt like one. Children were so different from how he was.
“I know there’s nothing wrong with me. I know it’s not a failing on my part, that'd be ridiculous. I was only curious.”
The curiosity ended, and Senku went back to things that made sense, mathematics. Because why would he bother if this didn’t affect him in the slightest. If anything, it was freeing that he didn’t have a soulmate otherwise Senku knew he’d want to look for them, or he’d always wonder. But when armed with the knowledge he didn’t have one, he was rather unaffected. What you don’t know, you won’t miss.