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The clues started early into their friendship, the first time she’d been invited to his house.
“Oh my goodness!” Yuzuriha grinned as she stepped into the little apartment, covered wall to wall in astronaut posters and space photos. There was a huge, shining telescope shoved off to one corner. “You guys are real fanatics!”
Senku cackled in his funny way, picking at some nonexistent earwax. “Damn straight we are. Byakuya’s almost as determined as I am to get the hell off this planet.”
“Byakuya- that’s your dad, right?”
“Yeah. I guess you could say that.”
“Does your mom like this stuff too?”
As little time as one year later, she’d have berated herself for prying; but being an eleven year old who was too curious for her own good, she was excited to learn as much as possible about her strange new friend.
Senku plopped onto a ratty couch with galaxy-themed pillows. “No mom. Just me and the old man.”
“Oh…” she internally cursed herself. “Please excuse me-“
“Don’t make things all weird in your head. Nobody died. Nobody that I knew, anyway. I’m adopted.”
He said it so casually, like it was an afterthought. It probably was. “I came here when I was, like, two. There’s never been anyone but Byakuya. And he’s never had much of a care for getting out there if you know what I mean.”
“Oh…” she said again, dumbly, trying to come up with something to say. “I’m sorry?”
He snorted. “Why?”
“Well. I mean, him raising a kid by himself…without a partner. And you not having a mom.”
Senku seemed utterly taken aback. “So? I’m not that high-maintenance.”
“No! It’s just…that sounds lonely?” Yuzuriha was aware that she was digging her own grave, but she’d been so shocked by such a concept that she spoke without thinking.
“He has me.” Senku said simply, sounding almost confused at the idea of his father wanting a partner.
That was the moment she realized: this boy genius had a bit of a blind spot.
The second time it came up was when Valentine’s Day rolled around.
The whole room smelled of cheap, sugary chocolate and hot glue from hastily put-together valentines.
She grinned over at Taiju, who blushed and gave a cute little wave. Very gentle, for such a big guy.
Senku, as usual, scraped his seat back unceremoniously and sat down in it backwards, grumbling to himself.
“Seriously, what’s all this fuss about. Just buy yourself the damn chocolate.”
“IT’S NOT THE SAME SENKUUUUUU!” Taiju bounded over. “IT’S A DISPLAY OF THE HEARTTTTTT!”
Senku groaned, plugging his ears and shooting Taiju a withering glare. “Must you be so loud in the morning, you big oaf?”
Yuzuriha came to his rescue. “It’s the intent behind them that matters.”
“Eh? The hell you mean by that?”
There was no way he was being serious.
“It’s an important tradition.” She explained. “To show affection, usually romantic in nature.”
“Why do we need a whole damn day for it though? If you like someone, you ask them out, build a relationship, mate, raise the next generation. Rinse. Repeat.”
He was serious.
“Senku…” she laughed awkwardly. “There’s no way any girl would be ok with that mindset in a relationship. You really don’t know anything, huh?”
Now he looked annoyed. “That doesn’t matter. As a scientist, I don’t have to procreate to contribute to the welfare of our population. I have other options.”
What. The.
“That’s…not-“
The bell rang.
Senku rolled his eyes and turned his chair around, leaving Yuzuriha utterly speechless.
When they gave the grade a sex ed class, though the boys were separated from the girls, they immediately huddled together after to share details and compare notes.
Taiju was pink in the face and shaking like a leaf, avoiding Yuzuriha’s eyes. Senku was as composed as usual, pinky finger digging into his ear as he rattled on about the scientific inaccuracies of the presentation.
“I don’t think anyone but you cares that much about the details, Senku.” Yuzuriha interrupted.
“It’s important to not misinform the next generation!”
“They didn’t have these classes throughout most of history, and humanity has still survived. This stuff is just in our nature!”
She rarely argued with Senku, because he had a tendency to be right. And annoying about it. But she’d realized long ago that this was a subject on which he had no clue.
There was a moment of silence. Senku’s brow furrowed, squinting at her like she was one of his experiments.
“Right.” He said finally. “Anyway, I’m pretty sure they did have some form of sex education throughout history, although that’s not my area of expertise. I’m a scientist, not a historian y’know.”
“Yes, we do.” She punched him lightly on the arm. “It’s all you ever talk about.”
“What is this shit?!” Senku grouched, in lieu of greeting as he stomped into the crafts club.
“Whoah, calm down!” Yuzuriha squeaked. “Don’t step in…the…paint.”
“Sorry.” He said curtly, having the grace to look slightly remorseful.
“It’s fine, it’s fine. Just get yourself clean-“ the words caught in her throat when she took a good look at him.
Because between his fingertips, held far away from himself as though it was coated in rat saliva, was a pink envelope. With a heart-shaped sticker on the front.
“Is that what I think it is?”
“I’d appreciate if you could tell me what you think it is, because I might be jumping to conclusions.”
“Could it be…! Gasp! blackmail…!”
“Be for real.”
“I think it might just be a love letter.”
“Ugh. I figured as much.” His face contorted to an image of such disgust that she had to hold back from laughing.
“Did you open it?”
“No. Why would I?”
“Aren’t you curious?”
Senku raised an eyebrow. “Not as much as you.”
Truthfully, she was particularly interested in the outcome of this interaction. In fact, Yuzuriha had a pretty good idea of who had sent that letter.
A few days earlier, her classmate and fellow crafts-club member, Yoshida Aya, had approached her, looking uncharacteristically hesitant.
“Hey, Yuzuriha…” she’d mumbled.
“What’s up?” She smiled warmly to put her at ease, but it seemed to have the opposite effect. Aya blushed and buried her face in her hands.
“I- um- god this is so embarrassing!”
“Take your time!” Yuzuriha had long accepted that she was the ‘listener friend’.
It was nice to help people out, even when she wasn’t totally qualified to give advice.
“You’re…always around Ishigami, aren’t you? And the big guy?”
“Senku and Taiju? Yeah, I guess you could say we hang out.”
“I see.” Aya seemed to steel herself, clenching her fists and finally looking Yuzuriha straight in the eye. “Does Ishigami have a girlfriend?!”
Oh no.
“Not as far as I know. Why do you ask?”
“Because…I, um. He’s…kind of cute, you know?”
She didn’t.
“And so intense! And really smart. And maybe, I was thinking…that…” she trailed off.
This would not end well for either of them.
“I don’t know if that’s a good idea.” Yuzuriha said finally.
“Why? I have the second best scores in our whole grade- oh no, that sounds really conceited, I’m sorry! But I’m not too stupid for him, right?”
“Of course you aren’t!”
“You don’t…like him, do you?”
Yuzuriha laughed. “Of course not! But…I don’t think you’d be a good match.”
“Why not?” Aya demanded.
“You don’t know him that well, but he’s super devoted to science.”
“Everyone knows that! I wouldn’t make him stop or anything!”
“He wouldn’t want anything to distract him from his studies. And, to be honest…” Yuzuriha didn’t want to say bad things about her friends, but… “he’s kind of an asshole. He’d be a crappy boyfriend!”
“Oh.” Pause. “Then what should I do? Even if it’s dumb, this is really distracting me! Should I tell him just to get it off my chest?”
Oh this poor girl.
“Maybe…write him an anonymous letter and see how he reacts?”
Aya perked up, throwing her arms around Yuzuriha. “You’re a genius, Yuzu-Chan!
So yeah, she had her suspicions.
Especially when she could feel a pair of eyes drilling into her back.
Senku rolled his eyes. “This irrational crap is ten billion percent more interesting to people like you and the meathead.” He tossed the paper in her direction, turning away as it fluttered to her desk.
“I- I can’t believe-“ Aya sobbed onto her shoulder. Yuzuriha held her tight, privately thinking that this was a lot of fuss over a guy she barely knew. She certainly didn’t get this emotional about Taiju- but then again, he did enough weeping for both of them.
Not that he had anything to do with this! Why was she even thinking about Taiju?
Not the time to unpack that.
“It’ll be ok.” She said gently. “Want to come over to my place? We can watch Stinky Beach Girl Mad Scientists 2: The Physicianing.”
“Nah.” Aya sniffled. “I’ll be fine.”
And she would be. Despite this momentary lapse of judgment, Aya was a tough girl. Yuzuriha was confident she could handle her first rejection.
Truth was, Yuzuriha mused as she walked home, there was no reason not to give Aya a chance. Maybe if she told Senku who had sent the letter-
No, that wouldn’t work. She was sure.
But why not? Aya was cute. She was incredibly intelligent, only behind Senku himself in terms of grades. She was nice.
Not that it wasn’t possible to just not have feelings for someone, no matter how attractive they were!
But Senku had tossed the letter away without even bothering to find out who sent it.
Which meant he was absolutely sure he wouldn’t be interested, no matter who it was.
“Damn, that looks rough.”
“Nah.” Yuzuriha shook out her bandaged hand. “Just got too cocky with the handheld sander.”
Senku had stretched himself out on her bed, lab coat casually tossed over one shoulder, one leg crossed over the other.
Yuzuriha herself was huddled in the corner with a pile of plushies, all handmade, her hands quick at work with the newest addition.
“Hey, Senku?”
“Yeah?”
“Are you asexual?”
She watched as his face morphed into utter confusion.
“You mean like a sponge?”
“No, like a person.”
She’d done a lot of research (three am google search), and was pretty confident in her conclusion.
“Humans can’t reproduce asexually.” Senku sounded disappointed, as if he expected her to be smarter than this.
“No just- aromantic? Maybe? Did I get the word wrong?”
“What the hell are you talking about?”
“Are you being stupid on purpose? I mean that you don’t like people like that.” She huffed, tucking her needle into the plush body and setting it down.
“You’re spouting nonsense. I like you and Taiju.”
“I mean romance and stuff. And sex, I guess. It said something about how they don’t go together? Whatever.”
The strangest thing happened then. Something she had never seen.
Senku looked lost. His brilliant mind was struggling to keep up with the information it had been given.
“I guess so.” He said finally. “If it’s a scientific possibility- and it’s very possible. A human can be born without entire chunks of their digestive system. Sexual and romantic attraction are much less integral to living, so I suppose-“
“Wait, really?”
“Absolutely. I was just reading about gastrointestinal diseases…”
“Not what I meant!”
“Wait, wait, it’s really interesting!” He proceeded to launch into a long explanation of short-bowel syndrome and missing guts.
As he rambled, her mind turned to something he had said earlier.
“Hey, Senku?”
“What is it now.” He grumbled, annoyed at the interruption.
“You like us.” Her smile turned mischievous. “You admitted it.”
Senku looked away. “I thought that much was obvious. Why else would I keep letting you guys come around?”
“THIS IS MY HOUSE!”
Such a strange guy.
Not that it mattered; it was fine that Senku was weird.
She was weird too, just better at hiding it.
She’d been told that her face turned absolutely terrifying when working on a crafting project.
She had a collection of hand made stuffed animals, all with names and occupations.
She had a meal plan for every day of the week, and insisted on cooking for herself so as to get the proportions right (she never ate at restaurants).
Part of the reason she had started sewing her own clothes was because of the annoying seams and fabrics in everything at the store.
And she never left the house without her seashell headband.
And when she was focused, everything and everyone around her disappeared. Leaving only room for her crafts.
So she could accept Senku being a little different, because he had always done so for her.
And a world with Senku always promised to be interesting, if nothing else.