Chapter Text
By and large, Senku isn’t someone who likes to dwell on things he can’t change, on doors that have closed. But he can’t help wondering what Byakuya would think, knowing he’s fallen in love with Gen Asagiri.
His dad had always retained something that people could dismiss as childishness, but with the distance of years and the clarity of grief, Senku can see it more clearly. His dad had never lost his wonder and his belief - in people, in science, in progress, in the everyday miracle of being alive. His dad loved fireworks and chasing the last slippery noodle at the bottom of a bowl of ramen, watching Senku learn to solder and listening to a song for the first time.
And he’d loved those ridiculous Gen Asagiri specials - the ones with glitter and misdirection, with psychological sleight-of-hand and faux mysticism, the ones that made Senku dismiss Gen as nothing more than a shallow flash in the pan. Byakuya used to watch them with Taiju and Yuzuriha, laughing in that open, guileless way of his while Senku scoffed from the other room, pretending not to listen.
Senku isn’t prone to regret. He’s built to move forward. But sometimes, he wishes he’d appreciated that part of his father more while he still could. Wished he’d told him that the thing that made him ridiculous to others was the very thing that made him extraordinary. Wished he’d told him he was listening, after all.
And now, across 3,700 years of silence, he feels that belief echoing through time. Through the recordings, through the Hundred Tales, through the very existence of Ishigami Village, his father’s legacy hums like background radiation. Byakuya had done what he could to make sure Senku had a chance - a chance to survive, a chance to build, a chance to dream.
Senku sees pieces of his dad scattered through the village, like stardust in orbit. Chrome’s boundless curiosity, the way Jasper squints when he’s trying to understand something, the curl of Ruby’s lips just before she tells a truly terrible joke - they all carry fragments of Byakuya’s spirit.
The ghost of his dad is all around him, scattered through forty people who would have potentially never existed if the world hadn’t ended. If Senku closes his eyes and lets go of logic for just a moment, lets himself believe like he did when he was a child, he can feel it. His father’s joy. His approval. In the way Kohaku teases Gen with exaggerated winks and elbows to the ribs, in how Kaseki insists Gen help with crafts, in how Ruri and Gen can sit quietly side by side, watching the wind stir the trees, saying nothing at all, in Suika’s soft, excited voice asking Gen for a story or begging to braid ribbons into his hair.
Senku is thinking about all this as he sits by the fire, the orange glow flickering against the copper and gold of the approaching dusk. Across the camp, Gen is putting on a performance. His voice is light and melodic, a touch too weak, one hand to his forehead as he leans just slightly toward Ryusui with a put-upon sigh.
“I would cook, of course, if I weren’t on the verge of complete collapse,” Gen drawls dramatically. “Surely a noble captain like you wouldn’t let a poor mentalist wither away from the sheer strain of culinary responsibility, would you?”
Ryusui, never one to resist theatrics or flattery, immediately bites. “We cannot allow that!” he declares, sweeping an arm toward the cooking station. “Stand aside, oh delicate flower. I desire you to remain fully operational!”
Senku, watching from his spot by the fire, doesn't even try to hide the snort that escapes him. Gen flashes a triumphant grin as he relinquishes the task, fanning himself with one hand like a victorious diva. The moment Ryusui turns his back, Gen's exaggerated limp vanishes, and he saunters over to Senku’s side.
Gen drops onto the log beside him with exaggerated grace, crossing his legs and leaning back on his palms. The firelight catches in his gray eyes, turning them amber and gold.
“Delicate flower?” Senku asks, raising an eyebrow.
“Not bad, right?” Gen murmurs under his breath, just loud enough for Senku to hear. “You’d think dear Ryusui would know better by now.”
Senku huffs quietly, a breath that’s almost a laugh. “You weaponize charm like it’s an elemental force.”
Gen shrugs one shoulder. “Can you blame me? Survival of the most dramatic.” He grins at Senku, like it’s a secret they share. The white half of his hair trails into his face. Senku’s fingers itch with the desire to tuck his bangs behind his ears, to see his clever eyes without obstruction.
Senku’s not one to be comfortable showing his feelings. His dad had been all heart, easy with affection, open in ways Senku has never figured out how to be. He wonders if that’s something you can learn, or if it’s just something that lives in your wiring. Because right now, with Gen sitting close and warm and smug beside him, he wishes he could reach across that narrow space and show him what’s coiled tight inside his chest like the gold wires they'd made.
When he had told Taiju, after the war, that he’d fallen in love with someone, he’d almost been more nervous than when he’d realized the conflict with Tsukasa was one that was going to have to come to blows. Taiju had shrieked, loud enough to startle nearby birds into flight. Then he’d thrown himself at Senku in a hug so suffocating it could have counted as a structural hazard. He'd blubbered something like, “Finally! I thought you were aromantic forever, and that’s totally cool, but - Senku! Love is amazing! I’m so happy for you, man!”
It had been mortifying. Taiju always hugged too tightly. But in that moment, it was exactly what Senku needed - that unfiltered joy, so reminiscent of the way his dad approached life, reminded Senku he wasn’t a robot, wasn’t alone.
The midst of rebuilding the world isn’t the right place to tell someone how you feel. The world was still cracked open at the seams. Every day was a battle of rebuilding, reclaiming, surviving. There were crops to tend, medicine to synthesize, machines to design. Feelings - especially messy, slow-burning ones like this - had to wait. Maybe forever. Too many people depended on Senku to guide them out of the dark.
Even Taiju, whose heart could rival a power generator for sheer force, hadn’t confessed to Yuzuriha yet. They circled each other like two stars in orbit, both fully aware of the gravity between them and still pretending they weren’t already caught in it. Senku understood the logic. It wasn’t the right time.
The softer side of him that takes so strongly after Byakuya, though, thinks it’s a matter of time. Gen had said he would fall into hell with Senku. Senku had taken up on it. They’re partners in this - in dragging the world forward, rebuilding it together.
One day, maybe, they’ll stand together at the edge of a city they built from scratch, looking out at the future they forged. Side by side.
Senku watches Gen across the flickering firelight, and for a fleeting second, he allows himself the indulgence of belief, of hope, in the way his dad would want for him. The illusion that maybe, someday, he’ll be brave enough to say it out loud. And that Gen will look at him the same way he is now - with firelight in his eyes and something like a secret in his smile.
“Is there something on my face?” Gen asks, one eyebrow raised, playful as ever.
“Nah,” Senku replies, not bothering to hide the lingering look. “You’re good.”
For now, he doesn’t need anything more than this: firelight, a heartbeat of stillness, and the silent promise of someday.
—
Senku had always thought the pain of a broken heart was hyperbole, played up for poems and literature, but he feels like he’s splitting in two as he marches away from Gen, leaving him next to the fire, looking confused, like he hadn’t known how deeply he’d just plunged the knife. Ten billion percent that I don’t even have the slightest hint of romantic feelings for Senku, Gen had said.
Senku’s chest feels like it’s collapsing inward, ribs constricting around something soft and fragile he hadn’t even realized he was still protecting. The air claws at his throat. He’s always had issues with his breathing - his unathletic nature doesn’t help - but now he feels like he’s suffocating.
And worse yet, people noticed. Ryusui is a chaotic menace, but he’s sharp and intuitive, and Senku knows, just from the look on his face, that he knows how Senku is feeling. Ukyo, ever attuned to quiet tension, had looked like he’d been physically pained by what he saw.
Senku’s always known he’s not as good with people as others around him. His dad had been effortless, warm in a way that invited closeness. Taiju was a golden retriever in human form, and Yuzuriha met the world with sincerity that never demanded anything in return.
Maybe that was the mistake. Maybe that made Senku believe he could interpret Gen’s signals as genuine. The teasing. The closeness. The way Gen always sat just a little too near, noticed when Senku’s hands were shaking from exhaustion, when the weight of the world was too much for his shoulders. The way Gen had stood next to him, like he had always been there and would always be. It had felt real. It had felt like a constant.
Now it just feels like he misunderstood the equation.
Senku’s not one to cry. Since waking up from the stone, he’s also not one to seek out solitude if he doesn’t have to - silence is oppressive; he needs the noise of people nearby to quell the faint panic lingering inside him when things are too still. But he’s wishing now no one was nearby.
He picks back up with Chrome and Kaseki on the design of the ship’s engines like nothing is wrong. The diagrams blur in front of him. He hears them talking, but it’s like they’re speaking from behind a pane of glass, the words slow and warped. He nods in the right places, makes notes with a pencil he barely registers in his fingers.
When it’s time to eat, he doesn’t even glance toward the fire where Gen sits with Ukyo. Gen still looks dazed, as if he doesn’t realize what he just said cut so deep it might never stop bleeding.
Instead, Senku takes his plate and settles beside Taiju and Yuzuriha. She looks surprised, her eyes flicking over his face as if scanning for cracks. Taiju, of course, is delighted by the proximity.
“Senku!” Taiju says, voice booming. “You never sit with us at dinner anymore!”
Senku offers a neutral hum in response, picking half-heartedly at the grilled tuna on his plate. He knows he should eat. He’s always struggled to gain weight. The Stone World, with its constant toil, hasn’t done him any favors. He’s not as strong as Chrome, not as sturdy as Kohaku or Taiju. Brain over brawn doesn’t mean much if the body breaks down. However, his stomach is tight. The food, despite smelling delicious, is the least appetizing thing Senku’s ever seen, including his first batch of badly-burned bread.
Yuzuriha leans over and pitches her voice low. “Senku,” she says. “What’s wrong?”
He swallows. She’s like the sister he never had. There’s not much he’s able to hide from her. “Gen doesn’t feel the same way,” he says, voice flat. He’s proud that it doesn’t shake, even if he feels like he’s being flayed alive from the inside.
Yuzuriha doesn’t say anything for a long moment. Then she says, quietly, “Oh, Senku. I don’t think that’s it.”
“Yeah,” Taiju says, shoveling food into his mouth so quickly that it’s a surprise he isn’t choking. “No one couldn’t love you.”
Senku manages a dry, humorless snort. “That’s not how any of this works.” He stares down at the plate of food in his lap. The sounds of camp and dinner rise around him - Ginro, arguing with Kinro about whether he needs to eat his kogomi, Kaseki and Chrome arguing about casting techniques, Minami and Nikki talking about every outfit Lilian wore on her last concert tour. Through the din, he can still catch the edge of Gen’s voice, saying something to Ukyo.
Ryusui plops down beside him with his usual flair and a loaded plate. The sudden movement makes Senku flinch, just slightly. He hates that. “Senku,” Ryusui says, pitching his voice so low that Senku almost can’t hear him, “Gen just broke your heart. Am I right?”
“You’re not wrong, at least,” Senku replies stiffly. Ryusui is a good friend, sharp as a knife - but he’s also greedy. It’s tempered by his kindness, Gen has assured him, but Senku feels raw and on-edge.
Ryusui mades a contemplative humming noise. “I think Gen is not aware of his own feelings,” he says. “The desire in his eyes when he looks at you! Something like that cannot be denied.”
Senku finally looks at him, eyes narrowing. “You sound awfully sure.”
Ryusui’s expression softens just a touch. “You weren’t famous, so let me explain something. In the modern day, when you were in a position like Gen and I were, it was much easier to be flat and never acknowledge what you actually wanted. I had endless wealth and no desire to lie to myself, of course. But Gen’s fame was based entirely on public perception, and we all know how easily that can shift.”
Senku doesn’t say anything, still staring at the barely-touched tuna like it might yield a new element under pressure. Ryusui watches him for a moment longer, then sighs, brushing a stray hair from his face with unnecessary flair.
“Gen lives in the gray area of understanding what he actually wants and what he needs to portray himself as wanting,” Ryusui says finally. He’s keeping his voice down, the quietest Senku has ever heard him be. “He’s made a life out of smoke and mirrors. He says one thing, means another. It’s instinct to him.”
“So I should what?” Senku says, sharp-edged now. The anxiety that Gen usually helps keep at bay is crackling through him. “Decipher him like a code? Assume he meant something else entirely when he told me, in exact words, that he doesn’t feel the same way?”
“I’m saying he panicked,” Ryusui replies, not flinching. “You ever consider that? Ukyo and I were pushing him. It was something we both felt he had there, but he wouldn’t acknowledge it.”
Senku grits his teeth, looking down at his food.
“I agree with Ryusui,” Yuzuriha says after a long moment. “Gen’s first instinct is still to say he’s shallow and a turncoat, even though we know that’s not the full story.” She glances at Taiju, who grins at her. It seems to hearten her, because she says, “Senku, you’ve always been the person who prioritizes actions above words. Gen’s actions have never made any sense without the idea that he’s in love with you. But he’s also pretty clearly never viewed himself as being worth that.”
Senku swallows. His food sits untouched. His hands tremble, barely perceptible - but Yuzuriha notices. She always does. She reaches out and gently covers his hand with her own.
“I don’t know what I’m supposed to do with that,” he says finally, his voice raw around the edges. “I’m a scientist. Not a mind reader.”
“No,” Ryusui says, “you’re the guy who is rebuilding the world. You’ll figure it out.”
—
Easier said than done, really. Senku can’t bring himself to talk to Gen directly for the next few days about anything deeper than the work that needs to be done. Gen’s personnel management skills are invaluable, so Senku will give him the laundry list of tasks to finish that day, and then escape before Gen can draw him into anything deeper.
Their Kingdom is still pretty small, and news spreads quickly through a game of telephone. Ginro seems to think Senku and Gen just had a fight. Chrome, who is often fairly oblivious, seems to be the one person who hasn’t picked up on anything at all. But a handful of others have started circling. Ryusui watches him like he’s trying to map Senku’s emotional blueprint. Yuzuriha offers quiet smiles and gentle touches on his shoulder, asking nothing but seeing everything. Nikki slaps his back, way too hard, and recites Lilian’s songs to him like they’re poems about pining. Even Ukyo lingers longer during conversations, as though he’s waiting for Senku to unspool.
Senku appreciates the kindness they’re showing him, but he's starting to resent it. His heart is broken. So what? He’s got to keep their full Kingdom chugging forward. He has to find oil, build a boat, figure out how everyone was petrified to begin with. His plate is full enough. His feelings for Gen were a distraction anyway.
At night, though, he dwells on it. He moved out of the tent he was sharing with Gen, and into one of his own. It’s the first time he’s slept alone since Taiju broke out of the stone. He can hear the noise of the camp in the distance, but to sleep without anyone’s soft breathing near him is unnerving. He’s been staying awake more often than not, tossing and turning. His sleep isn’t deep, and his dreams always cling to him when he wakes.
He’s feeling tense and on edge one afternoon, the kind of pressure that hums behind his eyes and builds like steam under a sealed lid. He’s triple-checked his measurements on the ship’s engine blueprint and still can’t shake the sense that something’s off - maybe with the numbers, maybe with himself. His jaw aches from how hard he’s been grinding his teeth, and the low-grade headache he’s been ignoring all morning is now pulsing behind his eyes like a warning.
He’s halfway through redrawing the intake schematics when Yuzuriha appears at his side, looking tense and uncertain.
“Senku,” she says gently, her hand brushing his shoulder, “Come with me for a second.”
He blinks at her, fingers still wrapped around his pencil, knuckles tight and white. “I’m in the middle of - ”
“You’re always in the middle of something,” she says, not unkindly, but with a firmness that brooks no argument. “This won’t take long.”
He sighs and scrubs a hand down his face, smearing a faint streak of graphite across his cheek. Wordlessly, he passes the blueprint to Kaseki, who takes it without comment, only offering a small nod and a rare look of concern.
Yuzuriha leads him away from the worksite, weaving through the village toward the shade of a tree just out of earshot. Once they’re alone, she folds her arms and glances up at him. Her expression is conflicted - there’s guilt there, and a flicker of something fierce behind her eyes. “Gen came to ask me what was going on with you,” she says without ceremony. She hesitates, looking conflicted, then exhales. “I yelled at him.”
Senku blinks, surprised enough to snort out a laugh. “You?”
She whacks his arm, gently. “I told him to leave you alone,” Yuzuriha continues, voice firmer now. “That he hurt you, badly, and you needed space. That if he wasn’t ready to be honest, really honest - not just with you but with himself - then he didn’t get to poke at the wound he made.”
Senku’s mouth opens, but no sound comes out. His chest is tight again, but in a different way this time.
“I don’t regret it,” she says. “But I also think he really didn’t understand how badly he hurt you. And maybe now he does.”
“Maybe you should be the lioness, instead of Kohaku,” he says instead of voicing the mass of feelings in him, ugly and messy.
Sometimes he wishes he could be a robot. A machine built for pure logic. No doubts, no spirals, no emotions fraying the edges of his thoughts. Just inputs, calculations, and clean, clinical output. That would be a far easier existence than this, than wanting something he can’t seem to stop wanting.
If he were truly logical, he tells himself, he’d have talked himself out of this mess by now. He’d have a mental list of Gen’s flaws etched onto the inside of his skull like a periodic table. How much he whines when there’s work to be done, how irritatingly committed he is to not wearing shoes, his wordplay that leaves Senku dizzy and scrambling to catch up, the way he cons other people into doing the dirty work for him. He’d see that, and snap his fingers, and return to his ground state.
Unfortunately, as rational as he is, that’s not how it works.
He’s tried, in the quiet of his solitary tent, to let go of it, that quiet, burning thing inside him. But it clings. It grows in memory. He keeps seeing Gen’s face when he revealed the observatory: that rare, open grin they shared, wide and full of wonder. He thinks of how they’d plotted to outwit Tsukasa’s empire, shoulder to shoulder, ideas flying faster than arrows. Gen, doing card tricks for Suika in the soft evening light. Gen, coaxing laughter from the exhausted workers after a brutal day. Gen, walking miles to guide Francois to the camp.
Senku’s chest tightens. He lets out a shallow breath, running a hand through his hair. His voice is raw when he speaks again. “I can’t stop wanting him.”
Yuzuriha tilts her head, giving him a soft smile. “I’m not a powerhouse like Kohaku is,” she says, “but I’ll always do my best to protect you.”
She leaves with gentle steps, and Senku watches her go until she vanishes behind a curtain of trees. Then, when he’s finally alone, he lets himself breathe. He leans back against a nearby trunk and slides down, settling into the leaf-littered ground. Rough bark presses against his spine. Overhead, the sky is a blinding, cloudless blue.
He wonders what his dad would say if he was here. He’d probably tell Senku to have faith in himself and in Gen. He'd probably tell Senku that he’s young, that they’re all still figuring themselves out. Shamefully, Senku can feel his eyes burning.
It occurs to him, in moments like this, how much he’s lost, how much is dependent on him. Senku’s biological parents had died before he could remember them, and he’d never really felt their loss - Byakuya was more than enough. But waking up to the stone world, alone, reminded him of how lonely he could be.
Six months alone, in silence, fighting nature for every tiny thing, before Taiju cracked open the stone with a roar and brought noise, chaos, life back with him. Then waking up Tsukasa, and knowing more or less immediately it was a mistake. Getting back Yuzuriha, only to lose her immediately.
Senku’s had to fight for every scrap of stability. Every connection. Every future. This world doesn’t preserve the things he loves. It shatters them.
And Gen…Gen is the first thing he’s let himself want, not for function, not for progress, but for himself. Gen is useful - he reads people like equations, navigates egos like a diplomat, and can lie through his teeth while disarming a mob. He keeps Ryusui in check, integrates the Empire of Might into the Kingdom of Science like they had never been at odds, runs cover when Senku needs it.
But more than that, he’s a partner. He might not know what direction Senku is going in, but he’ll match his pace. He throws himself into danger, just because Senku asks. He sees through Senku’s blase attitude to the core of him underneath - the side of him that is still a teenager, navigating an uncertain world, weighted with grief and responsibility.
The yawning void within him calls, the weight of everything on him, and this grief might just be the breaking point. He’s tempted to stay here, to let the earth swallow him whole, to let time pass by unnoticed, until the grass grows over his body and pulls him down into the dirt.
It’s melodramatic, but he’s eighteen. In another day and age, this would be okay to allow.
But for now, he has to keep going. There’s too much at stake, and he can’t risk stopping. Lives depend on him, people look to him for knowledge and guidance. He can’t do much about Gen, despite what he wants. He’ll just have to keep chipping away at this, until he finds the outline of who he was before he fell in love.
Senku heaves in another breath and hauls himself to his feet, carefully pulling himself back together before walking back to work.
One step at a time, he tells himself. That’s how it’s always been. It’s how things always get done.
—
The confrontation by the stream went disastrously. Gen had surprised him by cornering him so early in the morning, and his defenses had been down. And he misses Gen, in a way he can’t put into words - misses the way he hums to himself, misses the way he always know what Senku needs, misses the way Gen laughs, delightedly, when he successfully cons Ryusui into doing something for him.
He’s still sleeping badly, too. His dreams are fragmented and filled with shadows that leave his heart racing even after he wakes. Sometimes he wakes with dried tears on his face, feeling like an entirely different person, fragile and broken. In those moments, the raw longing for his dad grips him in a way that makes him feel like a child.
With everything else, it’s harder to think clearly, to reason through his decisions. And so, in a moment of weakness, Senku had caved. He’d hoped, against hope, that Gen might have felt the same. He’d told Gen the truth, the confession that had been simmering inside him for so long.
He’d always suspected that Gen had had some inkling of how he felt. Gen had seen so much more of people than he had, and he was glamorous, funny, sharp - there was no way a thousand people hadn’t confessed their love to him. Surely Gen knew what to look for. Surely he knew how Senku felt.
The shock on his face disabused Senku of that notion fairly quick.
His skin is crawling with embarrassment, but he’s able to hide it behind the rigors of their schedule. Bread does need to be made, and preserves started on, and Senku latches onto that excuse to get Gen away from him.
He knows what the others said - that Gen doesn’t know his feelings, that Gen cares for him deeply. But those reassurances feel like thin comfort in the face of Senku’s reality. The truth is, Gen’s feelings, whatever they may be, don’t align with the ones Senku had hoped for. And he is, unfortunately, still human. He feels the sting of it every time he looks at Gen. It hurts, but more than that, it lingers. It’s a sharp, persistent ache that refuses to fade.
For now, he needs space. He needs distance. He needs time before the sight of Gen’s face doesn’t send a spike of pain shooting through him, a pain so sharp it feels like a bullet lodged in his chest.
He doesn’t look at Gen as he orders people through loading the car, through dispatching Taiju with them. Taiju still fundamentally believes in fairy tales, in true love. Senku can’t explain everything going onto anyone, let alone his best friend.
Senku watches in silence as the car pulls away, Taiju waving energetically as they vanish from sight. The world feels quieter, somehow, without their presence. Without Gen’s presence. He hadn’t said a word to Senku before leaving, hadn’t even looked his way.
Senku swallows, the knot in his throat tightening, but he doesn’t let himself linger. He picks up his pencils and gets back to work.