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In another life, things might have turned out differently. A different set of circumstances, slightly different timing. But here is how it begins—with an end.
Both Taiju and Yuzuriha are present when Tsukasa confronts Senku at the bonfire. Instead of demanding the revival formula, Tsukasa says he wants to keep Senku around for his knowledge of making nital, edible plants, herbal medicine, and first aid, but requires that Senku completely renounce his goal of reviving all of humanity and reconstructing modern scientific civilization. Senku will still be able to practice this basic, “primitive” science for the benefit of others, but he will never be allowed to do anything else without Tsukasa’s express approval.
Senku of course refuses.
And that’s when Tsukasa decides to demonstrate just how serious he is.
He kills Taiju as an example, a warning. Senku and Yuzuriha are in complete shock as Tsukasa calmly says Senku has one more chance to say yes, clearly implying that Yuzuriha will be next otherwise.
Senku can barely process what’s happening—surely this is a sick joke of some sort, Taiju’s indestructible, he can't be dead. What the hell are you talking about? But after feeling for a pulse that isn’t there for far longer than would be reasonable, his disbelief is immediately replaced by a wave of grief that completely overwhelms him. It’s Senku’s own fault, he thinks. He was the one who wanted to burn the fire brighter, he was the one who poured the revival fluid onto Tsukasa’s statue. He’s the reason Taiju’s gone. He’s the reason Yuzuriha might—
Suddenly, the answer is easy.
“Okay,” he whispers hoarsely. “You win.”
Yuzuriha is horrified. Senku, giving up science? She grabs his shoulders and shakes him, tearfully asking him if he knows what he’s saying. Senku refuses to look at her, eyes fixed on Taiju’s corpse as he kneels beside it. The light has left his crimson eyes, and it’s as if he’s got no fight left in him.
Tsukasa says once they finish burying Taiju they’ll head back to Tokyo (well, what used to be Tokyo), and start reviving some key people he has in mind for building up a proper settlement. Senku merely nods, while Yuzuriha looks helplessly for a way out but can find none.
The process is slow, since Tsukasa decides it’s not his place to assist with the burial—he waits from just over the hill, close enough to hear if they try to run.
Senku and Yuzuriha stand side by side over the grave, dirt covering their arms and legs, mixing with the tears streaming down Yuzuriha’s face. Senku stares down at the mound of soil, ten billion desperate apologies sitting on his tongue. He swallows them down, because he doesn’t deserve forgiveness. Not when it’s his fault Taiju will never get to properly confess to Yuzuriha, when she’ll never get to accept. The beautiful wedding dress he knows she always dreamed of sewing will remain forever a fleeting concept, never able to find true form.
Why is Senku still alive when Taiju is gone? All the knowledge within his mind and yet he can’t bring him back. Useless.
But Yuzuriha is still here, he remembers. She’s still alive. So Senku has to stay alive too, for her sake if nothing else. They’ve only got each other now—her parents are missing, his dad is gone. He has to protect her, even if all he can do is comply with Tsukasa’s wishes.
Silently, he turns towards where the wrestler is waiting for them. Without looking at Yuzuriha, he extends a hand to her.
Without a word, she takes it and follows, their fingers intertwined as they leave their hearts behind.
The trek back from Hakone to Tokyo is fairly slow—Senku really rushed when Tsukasa was on their tail, but now that Tsukasa himself is leading the hike home (not that it can ever be home again, not with part of it left six feet under the Hakone soil), they’re taking it more leisurely, since Senku and Yuzuriha are far weaker than Tsukasa.
There’s zero talking besides Tsukasa’s decisions regarding food, water, and setting up a camp when the sun starts to dip below the horizon. Senku and Yuzuriha stick close together—though Senku trusts that Tsukasa will keep his word and not harm Yuzuriha so long as Senku complies, the thought of her leaving his sight for even a second terrifies him.
It gets worse when it’s time to sleep. Tsukasa is leaning up against a tree in sight of both Senku and Yuzuriha, curled up by another tree. They can hear him breathing, see the shadow of his muscles in the moonlight. Their best friend’s killer, right beside them. Eventually though, exhaustion overtakes them both, and they pass out.
Senku’s dreams are filled with blood spilling across the rocky hillside, and not just Taiju’s. He wakes up disoriented and hyperventilating, panic seizing his mind as he desperately searches for Yuzuriha in the darkness. Where is she where is she—
There. Lying right next to him, but is she alive? Senku reaches out, his hand shaking as he takes Yuzuriha’s wrist.
Her pulse beats underneath warm skin, and Senku can finally breathe again.
Unable to fall back asleep, he just lies there, fingertips resting on her wrist, counting each pulse of warm, unspilled blood as the sun comes up.
Before her eyes open, he pulls away, though a trickle of anxiety finds its way up his spine as he does.
They make it back to the trashed treehouse base, where Tsukasa has Senku explain the process for making the revival formula step by step. It’ll take some time for the cave to produce enough nitric acid for even one dose, so in the meantime Tsukasa goes on hunts for food and pelts to craft into clothes for the new revivals, as well as trips to find statues.
When they’re alone, Yuzuriha ventures a suggestion to run for it again, but Senku quickly and firmly tells her they can’t. She’s bewildered at how forceful he sounds—why has he given up on escape so quickly?
“We can’t live like this, Senku-kun,” she says. “Not with him. If we run, we can figure something out, we just have to—”
“NO.”
Yuzuriha is stunned silent. Senku’s eyes are wide and frantic. “It wouldn’t matter how clever or careful we were, he would find us, and we can’t outrun him.”
“But—”
“Do you think I want to stay? Every time I see him I—” he inhales sharply. “I’m sorry, Yuzuriha, I really am, but…”
He averts his gaze from her, voice wavering. “I can’t lose you too.”
The silence hangs in the air, Senku’s hands trembling in his lap.
“...There really isn’t a better option?” Yuzuriha asks desperately.
“...Well. There is one more option.”
“What is it?”
“I could distract him while you run back to Hakone to find whoever lit that signal fire and take refuge with them.”
Yuzuriha freezes. “What? And leave you behind?”
“It’s my skills he wants,” Senku murmurs. “And you’d be faster without me anyway. He’d lose his leverage, sure, but that wouldn’t matter. You could escape, find people to protect you—”
Yuzuriha grabs his hand tight, silencing him. “Never say that again,” she says, voice shaky as tears form in her eyes. “Never say anything about leaving you.”
Senku blinks.
“...Okay.”
The next few months are rough. Senku prepares revival fluid under Tsukasa’s watch, Yuzuriha sews clothes. As the new “Empire of Might” grows, the two of them draw further away from the rest of the group, only really interacting with the others when new revivals are required.
They hear about the smashing raids Tsukasa takes teams of men on, and Yuzuriha looks at Senku for his reaction, only to see him turn steadfastly back to the work he’s been assigned, not even a single word of snark uttered.
She thinks about their parents, teachers, neighbors, Taiju. She watches the other revived going about their new lives without questioning Tsukasa’s actions, without wondering why she and Senku never seem to talk to anyone. There is no Asagiri Gen to mediate things or to offer a kind word to her. There is only the storm in Yuzuriha’s mind, simmering.
Days are monotonous, Senku distilling alcohol, Yuzuriha tanning pelts and sewing. They don’t talk to anyone else but each other (and occasionally Tsukasa), and even then they say little. There’s not much to speak about.
In the evenings they lie side by side, watching each other breathing, waiting for exhaustion to take them. Usually Yuzuriha falls asleep first, and then Senku wraps his fingers around her wrist again, feeling her pulse. But then one night it’s her that wakes up a frantic, hyperventilating mess, searching for him.
After that, they start falling asleep with their hands intertwined, so that neither wakes up without knowing the other is there.
Time goes on. Senku and Yuzuriha only grow more codependent on each other, growing deeply anxious whenever they have to be separated. Senku in particular seems to become more and more tired as he continues to produce revival fluid and performs basic first aid for Tsukasa’s men. He has more energy when he’s collecting herbs and sorting poisonous forage out of their food, but every once in a while he opens his mouth to comment about something related to rocks and minerals or engineering and then decides against it.
Sometimes Yuzuriha catches him staring at the freshly distilled cup of brandy in his hands for a second longer than necessary before depositing it in the jug for mixing revival fluid in.
It’s killing him, Yuzuriha realizes. Being withheld from science, having to hear about the lives Tsukasa is destroying every day without being able to do anything about it, is killing him. But he’s enduring it, because he’s terrified that even the slightest bit of resistance would endanger her.
The grief fueled hatred that had already taken root in Yuzuriha’s heart is fed with even more resentment and frustration, and a plan begins to form in her mind.
What she doesn’t account for is that when she pulls her hand out of Senku’s in the dead of the night to begin enacting said plan, he immediately wakes up, a questioning look on his face.
He sees the clay bottle in her hand—asks her what it is. She gives a half answer. Brandy.
“What else?”
Yuzuriha hesitates for a second, before deciding she will not lie to him. “Aconitum.” It was fairly easy to crush up the poisonous plants and soak them in stolen alcohol to leach out as much toxin as possible.
It takes only a second for Senku to realize what she intends to do with it. He’s horrified, grabs her forearm and stares into her eyes as if searching for a trace of the innocent girl he grew up with.
“Don’t,” he whispers. “Yuzuriha, don’t.”
Yuzuriha’s heart aches, but she does not falter. “I’m sorry,” she says quietly, “but enough is enough. Someone has to stop him.”
She pulls away, and Senku watches her go in shock, unable to move his own feet. By the time he can move again, he realizes it’s too late. If he goes after her now, she might be discovered.
So he sits back down, desperately trying to make sense of it all, how they could have possibly gotten here.
Meanwhile Yuzuriha tips the concentrated poison down a sleeping Tsukasa’s throat, and counts down the seconds until she can no longer feel a pulse.
She supposes Senku hates her now. She’d thought about it, as she was making her plans. That she might be ruining their relationship for good. And still, she kept going.
It’s okay, she thinks, because Tsukasa won’t be able to hurt either of them anymore. They’re alive, even if her heart is on the cusp of breaking with no one left in this world who would care about her. She’ll go back to the room she shares with Senku, collect what little supplies she has, and leave.
When she returns however, Senku is waiting for her with a bag containing all their things already slung over his shoulder. As soon as he spots her, he runs over and grabs her hand, then pulls her away into the forest.
Yuzuriha looks up at him in astonishment. “You didn’t have to—“
“I know,” he murmurs.
But what choice did he have?
Murder goes against everything Senku was raised to believe. His father had always instilled in him a desire to protect all human life, encouraged his son’s interest in medicine and engineering solutions to improve lives, not destroy them.
But it’s Yuzuriha. As much as he hates the thought of killing another human being, Senku has been broken down by grief, having lost not only his father but his first and best friend, the one who brought such light into his life. He absolutely cannot lose Yuzuriha too—everything he’s suffered after Taiju’s death has been for her.
So he rationalizes. Yuzuriha did what she thought was right, to save the unbroken statues, to protect both of them. It was still wrong, but it doesn’t mean Yuzuriha is a bad person, right? And it doesn’t mean he’s a bad person, for having failed to stop her.
He does ask her to promise never to pull something like that again, for the sake of her soul and his. She holds his hand in both of hers and says of course, sounding breathless and relieved that he doesn’t hate her.
He could never.
They make it to Hakone and run into Kohaku, who recognizes both of them from the fire incident months earlier and offers asylum quite readily, as well as her sincere condolences for their loss. She introduces them to Chrome and he and Senku get along swimmingly, especially since Ruri’s illness is a problem Senku can actually solve.
However, even though Chrome is great and his warehouse of rocks has brought some life back into Senku’s eyes, he’s still in deep grief over Taiju and too reliant on Yuzuriha for emotional comfort (and the same applies for her) to really open up to Chrome as a friend. It still feels like Senku and Yuzuriha against the world, even as they express gratitude towards Chrome and Kohaku for taking them in—healing Ruri will be their way of paying them back.
But there’s a pretty huge problem with the cure Ruri plan—the Grand Bout is happening next week. Kohaku and Chrome have already asked for Kinro and Ginro’s support in trying to ensure Magma doesn’t win, but the prospects are rather harrowing. Thus, Senku and Yuzuriha find themselves entering in an attempt to help.
Unfortunately, luck is not on their side. Kohaku is disqualified through Mantle’s machinations, and Yuzuriha is pitted against Magma in the first round.
She forfeits as quickly as she can, but not before Senku is thoroughly traumatized by the thought of what could have happened to her at Magma’s hands, especially after Suika told them what Magma plans to do to Ruri if he wins.
With no time to have created scientific tools to give them an edge, Magma wins the Grand Bout, to everyone’s horror.
Something takes hold in Yuzuriha’s expression, and she looks at Senku. He holds her gaze for a moment, at first terrified, then resigned. His shoulders deflate, and he turns away.
“Do what you will,” he murmurs.
That evening during the celebrations, Yuzuriha slips something into Magma’s cup. Once everyone else is asleep, Kohaku drags the body into the lake, making it look like he got up to go to the bathroom, but stumbled into the water and drowned due to drunkenness.
Senku is awake the entire time, eyes closed as he listens for Yuzuriha’s return to his side. When she finally lies back down next to him, it’s with considerably more distance than usual. Senku opens his eyes, staring into hers.
She stares back, then slowly reaches her hand out, hesitantly. He grasps it firmly, rubbing his thumb over her palm.
His stomach still churns at the thought of the corpse in the lake, but how can he not forgive her? Besides, it was justified, wasn’t it? There really wasn’t any other way to stop Magma, right? Yuzuriha’s soul won’t be further tainted by this, right?
Right?
The next morning Magma’s death is discovered and after a bit of chaos, Chrome is made chief as the runner up of the Bout. He definitely suspects Kohaku of having orchestrated a murder and is rather conflicted about the whole thing, but steadfastly turns a blind eye to it, refusing to banish Kohaku for trying to protect Ruri.
Senku begins working on the antibiotic for Ruri, though there’s a bit of a concern over being able to get through the winter. Ruri also confronts Senku about his parentage, and the truth of the village is revealed.
When Ruri says the Hundredth Story has a message for Senku at the end, Yuzuriha offers to leave the two of them alone so Senku can hear it, but he asks her to stay. They stand over Byakuya’s grave together as Senku silently cries. Yuzuriha cries too, for Byakuya, for Senku, for Taiju, all the goodbyes they never got to properly say.
Seeing her crying, Senku promises that someday they’ll find her parents, swears on his own life that it’ll happen. Yuzuriha tells him not to make promises he can’t keep, but now that it’s in his mind Senku can’t let it go.
“Fine then,” she says, taking his hand, “but not on your life, okay?”
“...Okay.”
The winter months pass with everyone working on the antibiotic for Ruri. Yuzuriha and Senku manage to become comfortably amicable with the villagers, though they still get quite anxious whenever the two of them are separated for any reason. Senku’s regained a sense of purpose—they might not have revival fluid here, but he can bring scientific advancements to Ishigami Village that will save lives. It’s comforting, knowing he’s helping his dad’s descendants, and knowing that Taiju would approve of his actions, though his heart still aches fiercely thinking about him, and about what Yuzuriha did to avenge him.
Yuzuriha meanwhile charms everyone with her prodigious skills, which are quite valued amongst the villagers. Kaseki grows fond of her, and she comes to see him as a grandfatherly figure in the absence of her parents. Eventually, she even starts to catch the attention of some of the young men in the village, and one of them approaches her asking for her hand in marriage, much to her (and Senku’s) surprise. She says she’s flattered, but not interested. That seems to end things there, but it makes Senku think.
Late at night he suggests that maybe Yuzuriha ought to rethink the proposal, or consider the other men in the village as potential partners. He thinks Yuzuriha deserves better than to spend all her time with him, someone who’s too weak to protect her, who can’t give her romantic affection or children. He knows she can’t forget Taiju, but he wants her to be happy, and says Taiju would want the same.
Yuzuriha is quiet for a long moment, then softly says she believes being with Senku is the closest she can get to ever feeling happiness again, and she thinks it’s the same for him.
After a while, he sighs, taking her hand. “At least tell me if you ever change your mind.”
She nods, squeezing gently. “I will.”
Spring arrives, Ruri is cured, and Senku sets about trying to make more nitric acid the slow way for the ultimate goal of finding and reviving Yuzuriha’s parents, though he also starts working on agriculture for Ishigami Village.
All of a sudden, a group of haggard looking people appears over the hills. Knowing the only other people out there are members of the Tsukasa empire, the guards are immediately wary, until the leader steps forward—it’s Nikki, and she says they’re not here to fight. They just need food and medical assistance, and then they’ll try to move on.
That’s when Yuzuriha and Senku show up, and Nikki recognizes them, suddenly growing angry. She accuses them of having caused the ruin of the Tsukasa empire by murdering Tsukasa, saying it’s their fault that so many people have died.
Yuzuriha and Senku are taken aback—what is she talking about? Nikki says that after Tsukasa was found dead, Hyoga took over, becoming an oppressive dictator and refusing to allow anyone who got injured to be treated—if they survived on their own, then they would have proved they deserved to live, in his eyes. Disobedience was harshly punished, and those that didn’t work enough were even denied food.
The turning point came when Minami’s theft of some revival fluid was discovered, and Hyoga ordered Ukyo to execute her with an arrow. Ukyo refused, and Hyoga killed them both. That’s when the entire settlement splintered, with those opposing Hyoga’s leadership rallying under Nikki’s leadership to try and take control of the nitric acid cave. It didn’t end well, and so she and her surviving group members fled, deciding to go to Hakone—Tsukasa had told Nikki he suspected there might be another settlement of survivors there (he always did wonder why Senku, Taiju, and Yuzuriha had built such a visible bonfire).
Nikki says Hyoga said Tsukasa must have died of food poisoning, but she knew better. It was just too suspicious that Yuzuriha and Senku suddenly vanished around the exact same time. They must have killed him then, though she doesn’t know how.
Yuzuriha says Nikki shouldn’t direct any of her anger at Senku—it was her that killed Tsukasa all on her own, so any fault lies with her. The bitter and grieving Nikki says that she’ll be answering for her sins today then.
Before Nikki can move though, Senku puts his body between her and Yuzuriha, coldly saying Yuzuriha is the purest person here, for her actions saved the lives of hundreds of unshattered statues, and Hyoga’s actions have nothing to do with hers. If Nikki stands down, swallows her anger, and sees reason, they can instead work together to retake the nitric acid cave and stop Hyoga.
Nikki is still angry, but agrees, saying they have to make things right. And so begins the Stone Wars.
Besides radio communications, Nikki wants Senku to turn his attention to other technologies for the fight ahead. Camouflage, shields, defensive walls.
Weapons.
Nikki says there isn’t any hope for bargaining with Hyoga. Killing him is the only way she can see to make his men stand down. Senku argues that if they can sneakily take control of the nitric acid cave, then the threat of gunpowder weapons would force Hyoga to stand down, allowing them to capture him without having to kill him.
The debate continues for months, but then all of a sudden a group of Hyoga’s men shows up demanding that Nikki and the runaways surrender to them and return to the Empire of Might. Knowing that what awaits them is likely execution, to be made into “examples,” they refuse, and a fight breaks out. In the ensuing chaos, Kaseki is killed, along with some of Nikki’s people, while Kohaku manages to take out a good number of Hyoga’s soldiers using a single steel blade that Senku intended for cutting down trees. The rest escape, along with, to Senku’s utter horror, a captured Yuzuriha.
Any hope of total pacifism in Senku’s heart has evaporated, and he tells Nikki that he’ll work on designing those weapons she suggested right away. All he can think about now is getting her back, no matter the cost.
Yuzuriha is brought before Hyoga and fully expects to be killed, but instead he sincerely compliments her on her impressive assassination of Tsukasa—he actually witnessed her leaving Tsukasa’s quarters that night, and was amazed that someone so small and innocent looking could muster up the will to kill in such an efficient manner. Not to mention her other skills are nothing to dismiss either. How about they team up? He assures her that she and Senku will have a high position in his leadership if they turn over Ishigami Village and Nikki to him. All she has to do is say yes, and he’ll release her to deliver the message to Senku.
Yuzuriha asks what will happen if she refuses. Hyoga calmly says he’ll keep her alive as a bargaining chip until he has Senku in custody too, then torture them in front of each other until they agree. Yuzuriha politely thanks him for clarifying things, then says she’s okay with waiting.
Hyoga is mildly amused. Does she really think her allies have any chance against him?
Yuzuriha shrugs. “You’ll just have to find out.”
Back at Ishigami Village, Senku and Nikki have armed their forces with steel polearms, heavy crossbows, and carbon fiber shields, as well as preparing molotov cocktails and chemicals intended to knock out combatants, and defensive battlements to protect the village. Senku is so laser focused on the war effort that Chrome has to trick him into stopping to eat and sleep.
The death of Kaseki has affected them all too—the entire village is now wholly dedicated to avenging their fallen elder. Nikki and Kohaku work together to train the fighters, with a whole squadron dedicated to dealing with Hyoga alone.
Finally, Hyoga makes his move. He leads a battalion to capture Ishigami Village, forcing them on the defensive, or so he thinks. Because Senku and Nikki have already taken a strike team to the Empire of Might, communicating with Chrome who went ahead as a scout with the radio along with some of Nikki’s soldiers.
Nikki storms the nitric acid cave, while Senku heads for the prison Chrome scouted, laying waste to the whole area. A mad cackle of laughter tears through the air as fire and screams engulf the landscape. Senku feels like he’s on top of the world, satisfaction warming his heart as the bastards cry for mercy. Xeno was right, he thinks. This power, the ability to make your enemies cower before you, to regret ever crossing you…it’s delightful.
But when the prison is busted open, Yuzuriha isn’t there.
Senku stands in front of the empty room, then grabs the shirt of the guard in charge (Yo), his voice like ice as he hisses at him, eyes wide and wild.
“Where is she?”
It turns out Hyoga brought Yuzuriha with him to the siege on Ishigami Village, which to him has been going quite successfully. After breaking down the defensive towers, Kohaku has finally surrendered to him, and everyone has been rather compliant with him so far. The only issue is when he searches the village and discovers that that Senku, Nikki, and quite a few people seem to be missing…
Hyoga suddenly realizes his mistake, ordering his troops to return to the Empire of Might as fast as possible. They’re halfway there when suddenly the whole world starts exploding.
With his men either injured or scattering in fear, Hyoga grabs Yuzuriha and jumps up out of the smoke to a hilltop overlooking the battlefield, yelling that this is Senku’s last chance to surrender before he kills her.
When he gets no reply, Hyoga shouts that he’s counting to three. Yuzuriha stares up at his blade, angled at her heart.
“ONE.”
“TWO.
“THR—“
BANG.
Blood sprays across Yuzuriha’s face and Hyoga drops to the ground with a hole in his chest. She turns to see Senku holding a smoking pistol, his shoulders relaxing as he walks up to her and kneels down.
Senku reaches out and gently cups her cheek in his hand, wiping away the smear of red with his thumb and smiling softly. She reaches up and puts her hand over his, smiling back.
Senku helps Yuzuriha to her feet and their fingers intertwine, smearing crimson between them both.
All he feels is contentment. They’ll never be separated again. If she’s going to hell, he can walk right in with her.
Hand in blood red hand.