Uncertainty Principle
Seemingly against all odds, as the weeks pass, the Uchiha grow used to the Senju presence in their compound. In fact, as the medics’ intervention starts showing visible results in improving patient health and significantly lowering mortality rates, they are met with far less hostility and more cautious openness.
Surprisingly, Tobirama in no exception to this slow acceptance, though perhaps that is more to Kagami’s credit than the Senju heir’s. With the boy hanging off him like a stubborn monkey, Tobirama is far less intimidating. Not to mention how clear it becomes that the man has a soft spot for all children and struggles to refuse their demands for his time and attention as Kagami insists on roping him into including his friends.
Izuna watches as four Uchiha children simultaneously try to climb onto Tobirama’s shoulders while he valiantly attempts to keep them all from falling off. “He looks ridiculous,” he declares dispassionately, turning away once he has finished recording the scene satisfactorily with his sharingan so that he can look back and laugh at it on a rainy day.
The Senju medic he is escorting back to the guest quarters—is her name Itsumi or is that someone else?—snorts in response to his remark. “It is a common enough occurrence for us,” she says, smiling fondly as she watches her clan heir patiently herd the gaggle of dark-haired children. “When he is not in his lab or office, Tobirama-sama can usually be found training the young sprouts. Not that it’s any surprise since he is of both Senju and Hatake blood.”
Both cultures place great emphasis on child rearing and nurturing, Izuna has come to learn. Which isn’t to say that the Uchiha don’t, but it’s not treated as a community thing. Children are raised by individual family units and most people would hesitate in overstepping the child’s actual guardians and shy away from outright trying to parent them. From what Tobirama has told him, however, the Senju and Hatake raise kids pretty collectively. While the Senju still subscribe to biology in the bulk of their inheritance laws, the Hatake don’t even do that.
“He will make a wonderful father one day,” Itsumi says.
“He doesn’t want to,” Izuna contests immediately. When the medic blinks in confusion, he expands, “Be a father, I mean. He said he doesn’t want children of his own. That his brother’s would be enough.”
Itsumi doesn’t appear to be surprised, smiling sadly and looking back to where Tobirama is attentively entertaining the kids in the garden outside the guest quarters. “It’s no wonder,” she says softly, turning away. “I’m sure he decided as much after Itama-sama passed away.”
“One of his brothers,” Izuna guesses haltingly.
“The youngest,” Itsumi confirms, nodding. “Maiya-sama passed soon after his birth, and Butsuma-sama was never quite the same after that. The brothers only had each other to rely on. Had they been anyone else, the rest of the clan would have stepped in to look after them, but with clan heirs, the matter is more…”
“Complicated?” Izuna offers.
“Indeed. Propriety becomes a concern where it shouldn’t. Nevertheless, it was clear as day how much they adored each other. Kawarama-sama’s death hit them hard, but Itama-sama’s passing…fractured something. For both of them. I am sure neither is prepared for another loss like that.” Itsumi shrugs. “It’s why our honourable clan head came down so hard on the traitors who’d threatened Tobirama-sama’s life. This was the first execution order since he came into power, you know. He had them dismembered and didn’t even allow for a funeral or grave.”
Izuna’s eyebrows rise. That sounds like pretty standard procedure for traitors attempting to murder a clan heir, but he’s more surprised that someone was dumb enough to get caught concocting such a scheme in the first place. “Why’d they even try to kill him? I know they tried poison, but what really happened?”
For a moment, Itsumi considers him, clearly weighing whether or not she ought to divulge information to the enemy. Then she shrugs and decides it’s clearly not like the incident is being kept a secret, so why not. “They wanted him to lead the opposition against Hashirama-sama. There were talks of a potential coup if things went well. Obviously, Tobirama-sama disagreed so they tried to threaten him into it by microdosing him with the poison of an endangered plant that has no available antidotes outside the one in their possession. Whether or not they wanted him to die is unclear, but the attempt still counts, and no one was about to protest Hashirama-sama’s decision on a technicality. Certainly not when Tobirama-sama had to be kept in a coma for two weeks and couldn’t use his chakra for nearly a month after. They barely saved him.”
Izuna is quiet for a moment as he digests this. He’s made fun of the assassination attempt before and Tobirama hasn’t seemed too bothered by it, but it’s different knowing just how close the Senju heir had come to dying. Izuna wonders how long it would have been before he even found out.
He clears his throat and says, “I didn’t know Hashirama-sama had to contend with such strong opposition in his clan.”
Itsumi regards him carefully. “He’s a popular leader,” she corrects him firmly. “The clan loves him. He just doesn’t want war and he doesn’t hide it. That scares some people who’ve gotten used to the way things have been for far too long. In a way, it’s good that we’re rid of them sooner than later, before they could be allowed to do more harm.”
“Harm,” he repeats slowly.
“They led unsanctioned missions to deliberately provoke conflict, you know. There’s no telling how much blood has been shed because of them.”
Like the day they ambushed him in the woods. Izuna wonders just how many of those missions there were. He wonders if there are those with similar intent and actions in his own clan. Perhaps they should look into that and find out—challenging Madara’s authority is unacceptable after all.
“Well, I suppose we are fortunate that the assassination failed. Tobirama has proven particularly useful with his aid against this outbreak.” Izuna inclines his head. “And, of course, his babysitting services.”
Itsumi’s lips twitch and she turns to head back inside. “How odd to be hearing that from the mouth of Uchiha Izuna himself,” she remarks. “Truly, wonders never cease.”
Behind her back, Izuna rolls his eyes and waits until the medic has shut the door behind her to turn on his heel. It’s time for him to resume his ferry duties. “Hey, Senju!” he calls out to Tobirama, waving when the man looks up at him. “Time for your shift.”
Tobirama raises a hand in acknowledgment before turning to disengage himself from the reluctant brats. Izuna considers blowing a fireball in their general direction to get them to scram, but Tobirama manages to make his escape before he can attempt to bring the idea to fruition.
“They’re so sticky,” Izuna notes, clicking his tongue. “What is to become of the Uchiha if this keeps up?”
Openly rolling his eyes, Tobirama says, “They’re only children.”
“They’re our future,” Izuna insists.
“And they have plenty of time.”
Peering at his rival, Izuna says, “Is this some sort of elaborate scheme to try and weaken us by corrupting the future workforce.”
“Oh no,” Tobirama intones flatly, “you’ve caught me. Whatever shall I do?”
Izuna huffs. “Shut up,” he demands.
Tobirama snorts and pays him no heed as usual. Instead, he says, “I saw you talking to Itsumi earlier.”
“It’s a bad habit to gossip, Senju.”
“You are the last person I want to hear that from, Izuna.”
Deserved. Izuna shrugs. “She was telling me about the traitors of your clan.”
Something cold and unreadable passes over Tobirama’s face. “Ah,” he says, “I see.”
What an odd reaction. Izuna narrows his eyes and considers poking, but he doubts Tobirama will fess up to him of all people. Instead, he continues, “She also told me a bit about your brothers.”
At this, Tobirama stiffens. “What about them?”
“I forgot that you were among the oldest until they died,” Izuna comments. “We killed them, didn’t we?”
Tobirama lets out a long breath, his shoulders falling. He looks tired. Haunted, almost. Absently rubbing at his forehead, he says, “What’s your point?”
Izuna hums in his throat and considers his rival. “There’s no point,” he decides. Then, “I had another brother too.”
The Senju glances at him, face carefully neutral again. “I remember. He was the heir before Madara-sama.”
“His name was Akio.” Izuna swallows and looks ahead. “He died in a Senju ambush on his way back from a mission. I was on the mission with him.”
For a moment, Tobirama is silent. Then, quietly, he says, “I was too far away—in Iron—when Kawarama was killed, but when Itama died—I felt him fade away. I was too late by then. I could only bring his body back so he could at least have a funeral and his soul could rest.”
“I had to carry Akio’s corpse back home. It took me two days.”
Tobirama’s eyes are sombre when Izuna turns to look at him. “I didn’t know that,” he says, voice hushed.
He doesn’t offer an apologies or comfort. Izuna appreciates that. There is no forgiveness for something like that, no comfort to be found, and no number of empty words would change what has already happened.
“How are you still able to believe in peace between us?” Izuna asks quietly.
“It’s not like war will bring them back to us,” Tobirama says, and his eyes are weary with the weight of a lesson hard learned. “They’re already gone. The people still here though—we’ve still got a chance. We couldn’t save the ones we’ve lost, but if we do something different, maybe we can save the ones that are still around and those who are yet to come.”
And this time, Izuna doesn’t think of Akio with his anger and ambition. Instead, he thinks of Madara who loves and dreams and still has the rest of his life ahead of him.
Izuna turns to look ahead and chews on the thought. Finally, he allows, “Maybe.”
Izuna doesn’t know what he’s doing here.
He could’ve gotten out of his grandmother’s invitation to the shrine if he truly wanted to. Now that the disease outbreak is at a more manageable level, the clan is slowly starting the beginning stages of easing back into regular functioning and there’s a lot to be done in overseeing the process. Surely, he could find some sort of task to occupy himself with that would take precedence over visiting Chinatsu.
He'd even begun looking until he’d been informed that Tobirama had confirmed his own attendance because, apparently, this wasn’t a private meeting between grandmother and grandson, set up so Chinatsu could nag at Izuna about marriage, lineage, and whatnot.
Since Madara is usually genuinely too occupied with his duties to be bothered by these affairs, Chinatsu’s favourite victim tends to be Izuna. He has gotten very good at giving her the slip. He knows all the best hiding spots in and around the compound.
And this time would be no different had his curiosity not been piqued. He’d known that Chinatsu and Tobirama had met a few times now, but he couldn’t imagine what those two talk about. So, he’d willingly marched to his own suffering like a lamb to slaughter. Curiosity killed the cat and all that.
It turns out that, for whatever bizarre reason, Chinatsu is genuinely fond of Tobirama’s company.
Izuna hadn’t even known the old shrew was capable of such emotion. And for Senju Tobirama of all people? The woman sure has odd taste in acquaintances.
“So, you will return soon, yes, Tobirama-kun?” Chinatsu asks. “I see that the condition of the patients in the sanatorium is much improved.”
“Yes,” Tobirama confirms. “We hope to reduce all need for our assistance within the fortnight. From here on out, the Uchiha medics and a few volunteers should be able to handle the situation on their own. Of course, if need arises, we are more than happy to provide our services again, but we hope nothing so drastic occurs.”
“Indeed, I shall pray the clan be rid of this terrible plague.” Chinatsu sips at her tea. “You must be looking forward to your return. I am sure you have missed your family.”
The Senju heir inclines his head, his lips curving upwards almost imperceptibly. “It’s not so bad here. We are close enough that I can still sense my brother’s chakra and that puts me at ease,” he admits, “but I am needed back and so I must go. There are many preparations to be made after all.”
Izuna blinks. “For your brother’s marriage,” he realises. “It will be soon now, won’t it?”
“In a month and a half,” Tobirama confirms, nodding. “It is our turn to host our sister clan this time.”
So, the Senju compound will be acting as home to a bunch of Uzumaki until who knows when, after which some of them will probably stay behind forever to act as attendants to Hashirama’s future wife. Brilliant. More manpower to them, and that’s not even counting the resources they will come into in the wake of this renewed alliance. Izuna hums and turns to look back out into the courtyard.
His grandmother fixes Tobirama with a smile and dips her head. “May your brother and his to-be-wife enjoy a blissful union and a joyous future together.” She probably shouldn't be saying that so openly since there’s no official truce between the Senju and Uchiha, but aside from shooting her a narrow look, Izuna doesn’t voice his discontent.
As far as he’s concerned, the deities have long since abandoned them to their means. One silly blessing to the Senju main house isn’t likely to change that.
“Thank you for your kind words,” Tobirama responds politely anyways, though Izuna can’t gauge his sincerity on the matter.
“I wonder when it will be our turn to host a wedding for the Uchiha main house,” Chinatsu comments pointedly.
And there it is. Izuna sighs and lifts his eyebrows at her as if to say ‘Really?’, ignoring how he can feel Tobirama’s gaze trained on the side of his head.
Sniffing, his grandmother continues, “It’s high time, don’t you think? I’ve even volunteered to find someone for you—”
“Not Madara-sama?” Tobirama interrupts to ask.
Izuna snorts at that. “Have you met Madara?” he asks rhetorically. “He’s far too stubborn to agree to an arranged marriage. I don’t think he’s ever been interested in any sort of relationship for that matter.”
Chinatsu nods in commiseration because at least they’re both on the same page about this one. “He keeps saying that it will happen if it is meant to, but the man runs away at the first sight of romance. You’d think he’s allergic!”
“My cousin, Touka, is of a similar disposition,” Tobirama offers. “She simply isn’t wired for romantic partnership. Says she likes her solitude far too much to be in any hurry to give it up.”
“Yes, well,” Chinatsu huffs, “Madara is the way he is, and I have made my peace with that.” She turns to Izuna with narrowed eyes, “You, on the other hand—”
Izuna rolls his eyes and throws his hands up. “Here we go.”
“I simply don’t understand why you won’t let me find someone for you. You’ve agreed to it once already. Why not try again?”
At this, Tobirama peers at Izuna out of the corner of his eye. “You were engaged?” he asks curiously.
“Briefly. It was years ago,” Izuna answers, sighing. “We only made it past the first stage of courting before she confessed to me that she was already in love with someone else and simply too afraid to admit as much to her parents.”
She’d found the courage eventually. Izuna had encouraged her to. They couldn’t very well force her into anything she didn’t want. Forcing the heart to change like that simply doesn’t work for the Uchiha. It’s never worth the risk of grief-induced madness as is unfortunately common in their bloodline.
“And what a shame that was,” Chinatsu comments, an air of lament around her. “She’d been such a sweet girl, and she came from a good family too.”
“She’s married now,” Izuna tells Tobirama, ignoring his grandmother. “She and her wife adopted a baby boy last summer.”
“I see.” The Senju plucks up a sweet from the plate on the table and says, “I wasn’t aware the Uchiha arranged matches as well.”
Izuna shrugs. “We do, so long as both the parties involved are consenting of it. The courting period is a lot more rigorous though. The idea is that the arranged pair still be able to find a love match in one another. It’s always a fairly open-ended agreement so there’s less pressure if someone wants to back out.”
“That is how I ended up married to their grandfather,” Chinatsu says, refilling all their cups. She turns a stern eye to Izuna. “At least find yourself a love match if you won’t let me do it for you.”
He barely refrains from rolling his eyes again. “When I have the time to,” he tells her half-heartedly.
“You’re just wasting away all that youth and beauty.”
Desperate for a change in topic, Izuna turns to his rival and prays that Tobirama will throw him a bone. The Senju quirks a brow and eyes Izuna for a second before deciding to exercise some mercy and engage Chinatsu in answering his questions about what Uchiha wedding ceremonies look like. From there, they move onto talking about the spending habits of nobles in the capital, allowing Izuna to sit back and enjoy some relief from the old bat’s nagging.
Now that he has the time, he reflects on how odd it is to see Senju Tobirama sitting across from his grandmother in the heart of the Uchiha shrine, casually conversing as though nothing is amiss with the picture they make. It isn’t even as though Tobirama is particularly charming, nor does he try to be in his mannerisms. But perhaps that is why Chinatsu likes him. When he isn’t being a pompous ass, there is something rather honest about Tobirama.
It had caught Izuna off guard all those months ago, when they’d met in Iron. He’d been thrown off by the strange unexpected nature of Tobirama’s openness then, finding discomfort in his enemy’s willingness to share true thoughts with him. Now, however, Izuna is surprised to find that he has come to almost appreciate this aspect of Tobirama’s nature.
Izuna has been raised to be a diplomat. He knows how to lie right through his smiles, how to use gestures and charisma to his advantage, how to seduce and intimidate and converse through knives shielded behind pretty words. Sure, none of that has ever had any part in his relationship with Tobirama anyways since Izuna hasn’t wanted anything but violence and hatred there for as long as he can remember, and for most of that time, Tobirama seemed to reciprocate that sentiment.
But even now that Tobirama clearly has something he wants from the Uchiha—even if that thing is peace—he doesn’t put any bells or whistles on the notion and is more or less upfront about his ideas and wishes. In a way, it’s almost…refreshing.
Sometimes, when they aren’t bickering or factually discussing reports, they converse about their respective cultures and histories outside of one another or the age-old enmity of their clans, and Izuna finds himself stumbling over thoughts of the experience being pleasant. Tobirama is both known and unknown to him. He strikes an odd note between familiarity and intriguing newness that has Izuna lowering his guard and reciprocating his honesty before he even realises what he’s doing.
It should scare him. It should anger him. It just—doesn’t.
Izuna knows he ought to be glad that the Senju are finally approaching their departure. It’s been nothing short of stressful having them living alongside the Uchiha and running interference to mitigate any disasters. Still, he has to admit things could’ve gone a lot worse. In the end, the Senju had provided aid when the Uchiha had needed it most, and Izuna thinks it will be odd not to see Tobirama every day.
Or perhaps, more likely, he has simply lost his mind in an effort to cope with mental stress.
He is brought out of his musings by the doors to the room being slid open to admit one of Chinatsu’s priestesses. The woman who enters is obviously older than his grandmother, sporting a head of white hair akin to Tobirama’s and shrunken with age. Curiously enough, though her eyes are covered by a white blindfold, her head swivels around so her gaze would be fixed on Tobirama if she could see.
“Minagi,” Chinatsu greets, rising to her feet in one fluid motion. “What brings you here? Our appointment was for sundown.”
“I sensed a foreign presence,” Minagi says, head tilting. Her voice is raspy like the sound of snakes on a rock. Izuna presses down the urge to shiver.
Chinatsu glances briefly at Tobirama—the foreign presence in question—and then turns to say, “You must be referring to the Senju heir. He is an honoured guest to the clan.”
The chief priestess’s pointed urging for formality falls on all but deaf ears and MInagi hums with clear disinterest. Instead, she points right at the ‘honoured guest’ and says, “You. I can sense the scars on your soul.” At this, Chinatsu visibly falters and frowns, something almost like concern lined in the furrow of her brow as she too turns to Tobirama. “It is damaged. Unnaturally so,” Minagi continues. “You have walked out of the jaws of death and now its mark remains on your soul.”
Beside Izuna, Tobirama inhales sharply and stiffens, though his face reveals nothing of his thoughts.
“Minagi has a close connection to spirits. Sometimes, it lets her See some things beyond our realm of perception,” Chinatsu explains quietly.
“Beware, Senju-sama. The spirits have been agitated as of late. They whisper about something interfering with the balance of nature. Fate itself has become unpredictable. If I were you, I wouldn’t gamble with mine. Your soul is not stable enough,” Minagi says, and there is a certain gravity to her words that makes it seem like her voice is echoing in the otherwise silent room.
Slowly, Tobirama lets out a breath and dips his head towards her. “Thank you for the warning.”
For a long moment, Minagi is still, her attention still trained on the Senju heir. Finally, she asks, “Will you heed it?”
“I will try.”
Minagi’s lips twitch and she makes to turn away. “I will be Watching,” she announces and then she shuffles back out of the room without waiting for Chinatsu’s dismissal.
The breath that leaves Izuna is shaky. He turns to his rival and frowns at the cold contemplation on Tobirama’s face. It doesn’t seem like he is puzzled by the encounter at all, though Izuna finds himself rattled just by being in the same room. Clearly, the Senju has some idea about what Minagi had been referring to.
“What have you done, Senju?” Izuna asks quietly, and even that sounds cacophonous in the oppressive silence lodged between the three of them.
Tobirama turns to him, something like consideration in his eyes as he meets Izuna’s gaze unflinchingly and says, “I believe I changed fate, Izuna.”
“I hear you and the Demon are getting along well,” Madara comments with deceptive casualness.
Izuna carefully doesn’t stiffen or freeze. Instead, pointedly, he deflects, “I didn’t know you were keeping tabs on me. Should I be offended?”
Narrowing his eyes, Madara huffs, “Don’t be annoying. People have just noticed. It’s not my fault they’re volunteering information for free.”
He’s definitely keeping tabs on Izuna and just doesn’t want to admit. Madara only tries so hard to hide behind his hair like that when he doesn’t want to get caught because he knows he’s done something that could piss his brother off.
Izuna rolls his eyes. “We’re not getting along,” he refutes.
This wipes off the hesitant guilt on Madara’s face and is immediately replaced by raised eyebrows. “You haven’t fought each other in days,” he points out.
“I literally argued with him over lunch today.”
“And neither of you even reached for your weapons. Apparently no death threats were made either. Admit it: you’re getting along.” Before Izuna can gear up to make a death threat now, Madara’s face softens and he confesses, “I’m glad.”
Izuna falters. “What?”
Placing his brush down, Madara links his fingers together, hands resting on the table. “I wasn’t sure whether I really believed Tobirama’s claims of wanting peace. I doubted his sincerity, assumed he’s parroting Hashirama’s convictions to keep his brother happy even if it wasn’t something nefarious. After watching him over the weeks, though, I have to admit I was wrong about him.”
“What does that have to do with us getting along?” Izuna asks, scowling.
“If the two of you can set aside your enmity and grow towards cordial tolerance, even if it’s not true friendship, then perhaps there is reason to hope for peace after all,” Madara says, voice on the edge of halting as his demeanour slips into something cautious because he isn’t sure how his rationale will be received by Izuna who has defined himself by his hatred for far too long now.
Izuna purses his lips and bites back the instinctive defensiveness that rises in response to his brother’s words. He swallows. “Tobirama wants peace,” he says. “You and that stupid tree bastard want a village. There’s a difference.”
“Does the difference make you more likely to accept one over the other?”
“It’s a much easier pill to swallow,” Izuna admits hesitantly. “Not just for me, but for the clan at large. A village is...”
“Skipping several steps ahead,” Madara finishes, smiling wryly. “I know.” Still, his eyes are bright and his smile can’t seem to fade. “But if we can manage one, then surely one day—”
“Aniki,” Izuna interrupts warningly.
Madara’s smile doesn’t waver. “Okay,” he accepts easily. Looking Izuna in the eyes, he says, “Thanks, Izuna. It means a lot.”
Heat rushes to Izuna’s face even as a much more pleasant warmth unfurls in his chest at the sincere delight in his brother’s eyes. He can’t help it; he can’t remember the last time something he did or said made Madara so happy.
“There’s no need to thank me,” he says, waving the words off. “I won’t be completely sold on the idea until I’ve seen a finished draft for a formal peace agreement. Not only would we have to convince our own clan to even consider it first, we’re also assuming we haven’t irrevocably fucked things up with the Senju. Hashirama’s last letter to you was uncharacteristically formal after all.”
“Maybe so,” Madara acknowledges, “but we asked for aid and he did not turn us away. He’s hoped for years even when I did not. I can at least extend the courtesy of doing the same for once. I have to believe his actions count for something.”
Izuna crosses his arms. “Perhaps,” he relents after a moment. “It will still take us a while to get everyone in the clan on board though. From what I understand, Hashirama has been prepping his clan for the idea for years. We’re way behind.”
“I suppose we have our work cut out for us then,” Madara sighs, leaning back in his seat and already looking drained at the idea of the diplomacy that will need to be involved.
Biting the inside of his cheek, Izuna brings up, “I think I know of someone who would be able to help.”
Madara blinks, obviously intrigued. “Who?”
Dryly, Izuna asks, “Did you know our grandmother has grown rather fond of Tobirama?”
“Really?” A strange expression crosses Madara’s face. “What do they even—”
“Don’t ask.”
“And how do you know of this?”
“Don’t ask.”
“Thank you for inviting me,” Tobirama says softly to Kagami’s mother as he readjusts the sleeping boy in his arms, unable to resist the urge to gently bump his nose against Kagami’s, making the boy scrunch it up slightly even in his sleep.
Hanako watches with a faint smile and reaches out to smooth a hand through her son’s curls. “Of course,” she murmurs back. “Thank you for coming. You made Kagami very happy.”
“It was my pleasure to do so,” he tells her honestly. Every moment he gets to steal with his student, every smile or laugh he is gifted is a treasure that Tobirama greedily cherishes.
It must be written all over his face too because Hanako’s smile become knowing as she notes, “You love him.”
“He is very easy to love,” Tobirama says. “Kagami-kun is a blessing of a child.”
“He is,” Hanako agrees easily. “He loves you too. I can tell. He hasn’t gotten this attached this quickly to anyone before.”
“I am honoured by his regard.”
Hanako laughs at that, hiding her smile behind her hand. “What a thing to say about a seven-year-old.” Her smile fades, twists into something bittersweet. “It is a shame you must leave so soon. Kagami will miss you greatly.”
Tobirama’s grip tightens ever so slightly. “We will meet again.”
“And if it is on a battlefield?”
He looks down at the boy in his arms—his first student, a child he loves as one of his own, for whom he risked losing himself in between dimensions forever—and he admits, “I could not harm him.”
Hanako hums. “Make sure you say goodbye tomorrow. Kagami will be upset if he thinks you’ve forgotten him.” Her eyes grow cold, and she warns, “I will not forgive you if you break my son’s heart, Senju-sama.”
As far as he knows, Uchiha Hanako is not a kunoichi. She works in the clan archives and hasn’t received any formal training. Still, Tobirama does not discount her unspoken threat because he is sure she will find a way. Desperate, heartbroken people tend to.
So, he dips his head and carefully passes her sleeping son back to her as he promises, “You have my word, Hanako-san.” He steps back and nods. “I shall take my leave now. Thank you again for the dinner. I will be here just before noon to say goodbye to your son.”
Hanako nods back and waves him off, closing the door behind him as he leaves her house. Tobirama has not been assigned an escort in the past week—though Izuna seems to take up the duty unofficially on most days anyways—but he can sense the guard still attached to him as they follow him while he makes his way through the compound back to where the guest house is built on the fringes of the residential complex.
He slows when he passes the famed Uchiha firepit, caught by his own curiosity since he hasn’t had the opportunity to see it in either life. The firepit is an amphitheatre built at the heart of the residential complex, designed to essentially serve as a communal space for everyone to gather. From what he knows, the space functions both to host events like plays, speeches, announcements, performances, and to allow the clan to meet and mingle even when nothing is happening. It’s rather similar to the Hatake amphitheatre, though theirs is built around a stage instead of a bonfire.
While curfew had been levied, the firepit had been empty since everyone was discouraged from leaving their houses and interacting. Now that restrictions have been eased, however, there are a few people occupying the space, clustered and chatting amongst themselves. Someone has started a small fire and now it crackles merrily at the heart of the structure.
Tobirama would have strolled right past it, knowing how his presence might not be well received among the people looking to relax here, but then something catches his eye, and he stops in his tracks.
Seated in the row of seats right by the fire in Uchiha Izuna, looking pensive as he stares into the flames, his face washed aglow by the firelight. Perhaps he feels Tobirama’s gaze because, in the next breath, his eyes flick up and find his from across the amphitheatre. For a moment, Tobirama is caught, heart stuttering and half-convinced that the Uchiha heir has finally taken advantage of Tobirama’s foolishness in meeting his gaze head on because, surely, Izuna’s sharingan must be activated.
Izuna lifts his head fully and with the motion, the light shifts in the way it reflects against his dark eyes. Tobirama reminds himself to breathe again.
Slowly, Izuna inclines his head ever so slightly, tipping it towards the seat next to him. Tobirama pauses and considers, eyeing the few other occupants of the firepit before turning back to Izuna with pursed lips. Izuna lowers his chin and lifts his brows. An invitation and a challenge all wrapped in one. Tobirama sighs and, against his better judgment, accepts.
He doesn’t try to be unobstructive because there’s no point. Here, in this compound, he is noticeable regardless of his efforts. Conversations falter and halt as he descends the stairs into the heart of the pit, and Tobirama ignores the weight of the attention pinned on him.
Izuna’s mouth curves into something cruelly amused. “Good evening,” he greets, voice low, peering up through his lashes as if that would convince anyone against his devious nature.
Rolling his eyes, Tobirama drops into the seat beside him. “Hello, Izuna.”
“I heard you had dinner plans.”
“Yes.”
“Had fun?”
Tobirama hums his affirmation. “Any reason you’re here today?”
Izuna makes a thoughtful sound before saying, “It’s an easy way to see people without being too involved. Makes for nice background noise.”
“I see.” Tobirama peers over to the seat on Izuna’s other side, where a book lays with a bookmark placed towards the end. “Is that yours?”
Glancing over, Izuna picks up the book and says, “Ah, yes.”
The cover and title look familiar. “A classic,” Tobirama observes.
“You’ve read it?”
“I don’t read much non-academic literature,” he admits. “I do know that it’s tragedy though.”
Izuna’s smile is wry as he turns the book over in his hands. “I like tragedies,” he says eventually. When Tobirama raises an eyebrow at that, he expands, “There’s a certain comfort to them. Nothing is in doubt when everyone’s fate is sealed. The end precedes the beginning, and it happens right in front of you. I find a horrific kind of beauty in the futility.”
“The end precedes the beginning,” Tobirama repeats. He turns to look skyward, watching the smoke from the bonfire. “You know, the theory of special relativity suggests something similar.”
“Oh?”
“In relativity, space and time are not separate entities but are interwoven into a single four-dimensional continuum called spacetime, and events are described in terms of their position in both space and time. This suggests that when these events occur is dependent on the relative motion of the observer,” Tobirama explains. “In other words, if all events are fixed points in spacetime, that means that the past, present, and future coexist. They are all technically happening at the same time, and the way we understand them depends on where we ourselves are. Different observers might have different perspectives on certain events, so from a theoretical point of view, there is no such thing as a universal present.”
Izuna blinks twice, silent as he processes this. Then, frowning, he says, “Isn’t that kind of deterministic? You’re basically saying the future is fixed anyways so we only really have the illusion of choice. Reading it is one thing; living it is another.”
Tobirama counters, “Well, you could argue that free will and determinism aren’t totally mutually exclusive. Free will can be understood as the ability to act according to one’s motivations and desires, even if these are determined by prior events. So, in a way, even if events in spacetime are fixed, our experiences and choices are still meaningful within that structure.”
The Uchiha heir’s eyes narrow into a squint as he says, sounding unconvinced, “I guess.”
Unbidden, Tobirama’s lips twitch into a smile. “On a quantum level, events are actually described by probability instead of strict determinism. One way we reconcile this is by suggesting that all possible outcomes of quantum measurements do occur in separate, parallel branches of the universe. So, while each individual branch is deterministic, the overall structure itself is governed by probability.”
“You’re starting to lose me now,” Izuna declares. “How can multiple universes exist in one universe?”
“They’re branches.”
“Whatever.”
Tobirama snorts. “There’s also the theory of retrocausality.”
“And what the fuck is that?” Izuna asks, already starting to look exasperated.
“Some interpretations of quantum mechanics propose that future events can influence the past,” Tobirama says slyly, unable to help the grin that stretches across his face at the irony of this conversation. “Since spacetime would contain all events, this would include those where future and past interact in non-deterministic ways.”
Izuna throws his hands in the air. “How the hell would they even do that?!” he demands. “Listen, Tobirama, your physics is broken. Nothing makes sense. Reality is bullshit.”
“Reality is bullshit, Izuna,” Tobirama agrees easily. “Physics says as much in the uncertainty principle. There is no such thing as an objective reality.”
“Now you’re just messing with me,” Izuna huffs.
“I’m not,” Tobirama assures. “The uncertainty principle says that it is impossible to simultaneously get an accurate measurement of both the position and momentum of particles. While we observe one, the other will change.”
Frowning, Izuna says, “So?”
“So, the particle basically materialises when we measure it, but before we do, we don’t know for sure where it will go. Wave functions exist for us to make guesses based on probability, but they aren’t deterministic,” Tobirama explains. He turns to Izuna and says, “This means that, on a quantum level, no objective real world exists outside of the way we choose to perceive and measure it. Your reality is quite literally what you make of it.”
Izuna furrows his brow, tilts his head just so, and Tobirama is startled to realise that the faint scarlet glow of his eyes really is the sharingan this time. It doesn’t even look like Izuna himself has registered it. “Basically, you’re saying that—”
Voice growing quieter, Tobirama interrupts, “I’m saying that we understand reality when we measure it.” He pauses. Then hesitantly, he simplifies,
“You see me. You look at me, and I exist.”