Chapter Text
Kai, as a rule, were largely immutable. They aged but only imperceptibly, as stars. They were creatures of routine, entrenched in habitual actions and thoughts alike. Even on those rare occasions they changed their minds, the shift was nothing short of glacial. Zamasu knew this all too well.
Yet Zamasu—the other Zamasu, the one the mortals had taken to calling Black—was as ever the exception, and Zamasu knew his secret. A clean break. As forcefully, shatteringly clean a break as possible. Not days after he met Goku, he’d already cast everything aside—his master, his home, his body…everything but his dream. With that dream, Black had come to Zamasu and tried, consciously or not, to give him the same. He would come and be free. The super dragon balls awaited, and once Zamasu used them, he too would have no reason to return to his old home.
Gowasu was dead. Zamasu, both of them, were Supreme Kai. The twelve universes, vast and wide and entirely theirs, awaited. And yet Zamasu lingered.
It was night that bothered him, he explained. He was too accustomed to the ever-brilliant World of the Kai, where even at night the sky glowed ethereal gold in the light of the moons. He’d spent millennia there with Gowasu, peering down into crystals and mirrors, focusing their godly sight upon, all too often, one or another tribe of mortals threatening to bring disharmony to their world. Looking down was gazing upon strife, endless strife, but looking up was a reprieve of cherry blossoms dancing in the breeze and clouds twining through the sky.
On mortal worlds, at least at night, up was the direction of stars. The view became a scattering of points that invited Zamasu to pick one and focus in, in, in until he wasn’t looking but seeing a world in its star’s reflection, and every mortal on it. The loathsome, foolish creatures. His blood boiled at the sight of so many of them yet alive. There, at night, the sky was filled with scum. To be so surrounded was more than Zamasu cared to tolerate.
And yet with every planet they visited, the feeling promised to ease. They were making progress, slow but inevitable, and Black saw the stars as jewels. He didn’t share Zamasu’s sight anymore, at least not fully. Aspects of it were physiological, they’d learned, not merely technique. It took intense focus for him to turn his sight on distant worlds, but when he did, he smiled.
“With each generation, their sins will only grow,” he said with a laugh. “Just as we grow more capable of punishing them to the fullest extent.”
His assurance brought Zamasu's disgust to heel for a time, but it didn't pass on the same vicious joy that drew Black's eyes beyond the horizon. Even caught on all sides by the press of humanity, Black saw only an opportunity to hone his will against them.
“And yet their sins bring harm not only to themselves,” Zamasu heard himself answer. “Some mortals threaten the very balance of their worlds, even now. It would be prudent to target them first.”
The fastest way, naturally, would be to travel to the Sacred World of the Kai and use a scrying orb to find them. Zamasu both hated the night and no longer needed to sleep. He made the natural volunteer.
It was an undeniable excuse to linger. Zamasu knew it—knew why he'd said it—and could only wonder if Black sensed it too. He’d said nothing but only, perhaps, because there was nothing to say. The work of Supreme Kai was necessary, and it would be many times more difficult than before. Zamasu would be alone, with no lower Kai to assist, attempting to oversee all twelve universes. It meant long stretches of gazing down upon the worst of humanity held between days of joining Black in exterminating the vermin themselves and drinking in the sight of their handiwork.
Only days though, on those mortal worlds, and the odd smoke-clouded night. When it cleared, Zamasu was back to the realm of the Kai, as per his perfect excuse.
He still had the choice, though, of how close to home he lingered. Even counting only the Supreme Kais’ home worlds, it rounded off at an even dozen. Universe Seven’s was metaphysically closest to Black if Zamasu wanted to be practical, but instead, he found himself returning every time to Universe Ten. He sat in the shade of the same tree, drank the same tea, and gazed into the same crystal ball. It was far from identical, though, and he reveled in the differences, or really the one difference: no Gowasu sitting across the table from him, oh so fondly trying to steer Zamasu from anger to reluctant, even callous acceptance. How many millennia had Zamasu let it go on? How many more would it have continued if not for his other self stepping in?
Too long, Black would say.
It was all too easy for Zamasu to close his eyes and imagine Black there with him, casually comfortable across the table in Gowasu’s chair. As well, it was the easiest way by far to silence the ghost of Gowasu lingering with Zamasu in their old haunts, blindingly patient and forgiving as ever. The memory of his concerned gaze bore down upon Zamasu until Black leaned in and dashed it to ribbons, eyes gleaming with violence. He’d look to the crystal, waiting for Zamasu to guide their sight, and Zamasu, focus recovered, would oblige and disregard the ease with which he’d manipulated himself.
He pretended, too, that he didn’t notice how readily he'd settled Black in Gowasu’s seat, a radical change but at once no change at all. Black was no Gowasu. He was passionate, powerful, and adamant in his beliefs. He took the reins of the universe and pulled, and therein lay the parallel Zamasu couldn't deny. In killing Gowasu, Black had freed him, yes, but in the same act he'd earned a claim neither had intended to give him, a right to Gowasu’s authority as mentor.
There lay the hardest truth of all to keep buried: Zamasu was doing exactly as poor a job as he had with Gowasu of taking Black's lessons to heart. That authority meant nothing if they both ignored it, but here Zamasu was, refusing to let go. His very presence upon the World of the Kai was a strike against him. He wasn't meant to be on this old world, retracing old footsteps. Not anymore.
Most days, the awareness of was only a chore to bury. Some days, though, it forced itself like a wellspring to the surface. Some days, Zamasu could barely keep his sight from wandering to whichever heretofore godforsaken rock Black happened to be on, checking if dawn had yet reached his longitude—and those became a sign that he needed to go home. A sign that he wasn't home anymore, and for all he'd put it off, the weight of realization caught Zamasu momentarily off-balance.
All in all, off-balance wasn't an uncommon feeling nowadays, but nor was it altogether unpleasant. Night remained loathsome, but as the weeks wore on, Zamasu found dawn was becoming tolerable. Intriguing even—a bloom of color across the sky, a flood of fire to chase away the night. Black always joined him in watching it, having sensed Zamasu's ki the moment he arrived on-planet, and Zamasu knew in that moment, no matter what distance remained between them, their thoughts were aligned. This was only a pale echo. The true cleansing fire was yet to come.
Cosmically speaking, Kaioshin were solitary creatures. As a people, they were long-lived and insular, shaped by their duty to maintain the universe’s order. If ever Zamasu hesitated at the thought of walking his path alone, it hadn't been for long. Such a life was inevitable, and he’d never been one to abandon his duties. One day Gowasu would retire, and Zamasu would take up the mantle of Supreme Kai in his stead, standing by nature above and apart. And yet…
Distracted again, Zamasu?
And yet there was something to be said for savoring every moment of good company while he had the chance, even when it wasn’t real.
If you’re going to keep looking to the planet I’m on, you should come see it in person.
There was a razor edge to Black’s voice that promised bloodshed, an offering held forth to call visitation from his god.
“In case you’ve forgotten, Zamasu, you are asleep,” Zamasu muttered, dismissive. He blinked, and the image in the crystal shifted, blurring to smoke before resolving to a nighttime view of their latest abode. Gentle, moon-streaked waves lapped against the piers of a bungalow pressed flush to the edge of the sea. No light came from inside.
I would wake the moment you arrived.
Zamasu could only guess sometimes if Black’s imagined running commentary was true-to-life or merely his own wishful thinking. A wave of his hand dismissed the view through the crystal ball.
“I can hardly be blamed for being drawn to this planet. My search is for worlds thrown into chaos, and the one you happen to inhabit is so overwhelmingly wretched as to overshadow all others.”
He looked up, knowing the seat before him would be empty. No Black, no Gowasu, and it mattered not at all. Zamasu stood and turned away, taking slow steps from the table as he spoke.
“If humans show their true colors before they die, then these are undeniably among the worst of the worst. Tell me, how many resisted? How many hid or begged? A few perhaps, as individuals, but as peoples, they chose to spend their last moments waging meaningless war against one another. With nothing at stake and nothing to gain, they let their weapons fly. Are these the creatures we were called to protect? The gods granted them sentience, but nothing has stemmed from it but barbarity.”
Black scoffed. They did spare us the trouble of destroying their cities. How like him. The anger in his voice wasn’t only at their brutishness, Zamasu imagined, but at losing the opportunity to do the job himself.
“And granted us instead the tedium of tracking the survivors to fortified bunkers,” Zamasu followed.
Then join me. We’ll blast their walls to rubble and move on before they can do more harm to their world.
“But where will we go next?”
Zamasu looked over his shoulder, but of course, Black wasn’t there. Not that he would have had any answer beyond an amused shrug.
Truly, it was terrifying how easily Black could make up his mind, often more than willing to decide on the spot. It must have been practice—practice Zamasu hadn’t gathered sitting at Gowasu’s table for days on end, serving tea with a clouded swirl and a bitter tang only Gowasu could taste.
He used the same leaves every time, the same technique honed by endless centuries of practice. The tea had tasted no worse than ever to Zamasu’s palate. It was an overreaction, he'd thought, but Gowasu was not Supreme Kai for nothing. Zamasu couldn’t deny anymore, on the odd occasions Black poured tea for the both of them, the almost subliminal sweetness that lingered on his tongue—not a presence of sugar so much as an absence of conflicting notes.
Zamasu never mentioned the difference beyond the usual compliments, but Black had to know. The tea was an unspoken, preemptive counter to any argument, a winning hand laid flat on the table. Even inhabiting a mortal body, it was he who remained purer of heart.
His clean cut, his chance to free himself—it had to be the reason. With one stroke, Black had killed his timeline's Gowasu and made his mind up once and for all, and with another he'd denied Zamasu the chance to do the same.
Zamasu held no spite for the act. Nor did he regret it. He couldn’t regret even a fraction of the joy Black had brought to his life, but he’d missed his chance. The moment passed and left him in the drawn-out tail of letting go, wandering the same paths he’d wandered for centuries. Even the grass was familiar, down to the blades. He could change it—he was master here now—but his place was on distant worlds completing his work, not landscaping in the realm of the Kai. Too many had made the same mistake already.
And yet it eased his heart to walk through the gardens. This world had thrived at Gowasu’s hand. Soft spot for mankind aside, no god of creation was without a finely honed sense of artistry. A gazebo stood among a ring of flowerbeds, and in its shade were two seats, a table, and a round mirror inlaid in the center. Here Zamasu could continue his work as a new order of Supreme Kai. He’d sit, scry a course across the universe, and join Black when the time came. It would be no lesser an undertaking than eliminating mortals by his own hand. No easier, no less vital to their cause, and no less fulfilling.
No matter where he was, every moment of Zamasu’s immortal life would be brimming with joy now—joy and a sheer existential exuberance at having met a companion who understood, at finally doing what he’d known for centuries needed to be done. He was happy, here and now, and yet, and yet, and yet—
If he didn’t leave, how much longer would he stay?
Zamasu's eyes were closed when he warped not to the shore or the deck of the beach house, under the baleful stars, but to the side of Black's bed. Even so, it was hard to make out the other’s face in the sudden dark. Zamasu only had the fleeting impression of someone other before Black’s eyes snapped open, drawing his features into a familiar expression.
“Zamasu? Is something wrong?”
“I—” Zamasu’s train of thought, scattered as it was, skipped completely off track as Black sat up and the blanket slid from his shoulders. “Why aren’t you wearing a shirt?”
Black blinked a few times but relaxed anyway, swiftly realizing Zamasu wouldn’t waste time on such frivolity in an emergency. “I am… unaccustomed to requiring so much sleep,” he said hesitantly, as if struggling with an embarrassing fault. “But this body becomes unresponsive without it. I’ve been accommodating its habits to make the process easier.”
“You’ve been sleeping in the nude?”
Black shot him a look. “I’m wearing pants. Is this what you woke me up for?”
Of course not. Black was trying to pull the conversation back on topic, but Zamasu didn’t have an answer. The more he sought to put it into words, the more absurd it became. He’d needed to leave, suddenly and irresistibly, so he had. The clarity of it would make perfect, obvious sense to Black, but that was the problem. It wasn’t so simple.
Regardless, at a loss for words was not a normal state for Zamasu, and Black set the attempt to question him aside. He pushed himself out of bed, fulfilling the promise he’d made in Zamasu’s imagination, and stretched his arms above his head. For lack of any better means to break the silence, Zamasu chose to comment.
“You look different.”
“Oh?”
“Less bulky.”
Black smiled at that. “Son Goku squandered his potential striving for power with no regard for form. Some of those habits, I’ve managed to break. We should spar again.”
Zamasu knew the habits Black referred to. He’d seen them firsthand in their earliest sparring sessions. Black would raise an arm to block an unexpected attack, then scowl at the instinct. In his original body, he’d trained to raise a palm instead, redirecting the blow and making space for a counter.
His blocks were the clearest sign of a difference but not the only one. There were subtleties of posture, balance, and musculature that clashed with Zamasu’s fighting style. Goku threw punches from his arms and chest. Zamasu’s were rooted in his feet and in steady lines drawn through his core. Goku kept his weight centered. Zamasu let it flow with his blows and around his opponents'.
It wouldn't do to simply replace Goku's fighting style with Zamasu's own, though, or so Black said. A Saiyan's body needed to fight as a Saiyan, but now as a Kai as well. He spoke of integration, adaptation—all repugnant in Zamasu's eyes, yet he couldn't deny the results. Sparring with Black never failed to prove entertaining.
“Yes, let’s,” he said, but Black held up a hand.
“Breakfast first. Would you make the tea?”
Of course. His mortal needs. Zamasu nodded and made to leave but paused in the doorway. He still hadn't said why he was here, and the request for tea had all the air of a subtle test. A redundant one to be sure, and inconclusive at that. Neither of them had Gowasu's taste, and the conflict in Zamasu's heart would have been obvious the moment he arrived unplanned and unannounced.
It had chafed to be the victim of Gowasu's concern, but it stung to be the target of Black's, infrequent as it was.
Zamasu glanced back over his shoulder, only to catch Black's head popping free of his collar as he tugged a shirt on. His eyes crossed briefly to glare at his hair, and Zamasu felt the sudden need to suppress a laugh. Concerning or not, he couldn't regret coming here—couldn't regret a thing at all.
“It's good to see you,” he said by way of explanation, and whatever Black took from that had him smiling too.
“You as well.”
The sincerity in his voice shouldn’t have been such a comfort. Black’s words were only a reminder. He’d been the one to seek Zamasu out, and Zamasu knew he’d wanted more than a measuring stick for godhood. He knew it as well—better even—than he knew himself.
There was never any predicting how a sparring session with Black would end. As the more powerful combatant and nearly always the more invested, Black set the pace. Some days he was content to play and let the fight become a backdrop to their conversation. Other days he seemed intent on exploring the depths of Zamasu’s immortality, an exercise Zamasu indulgently allowed. And then there were days when he drew his focus on going back to his roots, tracing Zamasu’s steps and following his attacks until they moved as perfect mirrors.
Black was always closest to his old self with an energy blade at hand. Son Goku had no muscle memory for striking with the edge of his fingers, a flaw Black was determined to remedy.
They started slowly by the standards of a Saiyan, exaggerating their motions to etch the patterns into the core of Black’s body. It was less a fight at that point than a synchronized training regimen, but Zamasu didn’t mind. He’d spent centuries memorizing the forms, drawing forth his ki and honing it to a razor point. What were a few hours more when time itself was theirs? It was worth it to see Black’s delight—the satisfying ache of flexing little-used muscles entwined with his perverse pleasure at making Goku’s body his own.
It couldn't last forever. Decisiveness, not patience, was Black's strong suit, and sooner or later he'd go for the kill. The literal kill at that, or what would have been on anyone other than Zamasu. Rarely was the blow too fast to block, but he aimed for moments of distraction, gaps in time when Zamasu was too caught in the rhythm of their match to react. Zamasu's throat would weave back together, and he'd return Black's vicious smile with a grin of his own. Then the real fight would begin.
It was an uphill battle every time. Even out of shape, Black was undeniably stronger and faster. Goku had ample practice limiting his strength though, and Black measured his to be a fraction above Zamasu's own. Zamasu knew his game. He could feel himself being forced to step up and grow stronger for it, even if Black's motives were ultimately selfish. He wanted a better sparring partner, simple as that, and for him, Zamasu was willing to oblige.
Inevitably, as Zamasu pushed the limits of his reflexes and Black the limits of his body's fluency with a blade, they fell upon the roots of their shared training—stances, forms, sequences of attacks and parries adjusted subtly for flight. They returned to mirroring, synchronizing their motions and even their ki until one day they reached a perfect match. Their blades didn't clash but merged, and Zamasu felt his knuckle crack at the impact with Black's. It knit itself together even as Black grabbed his hand and laughed, pushing energy into the connection in a move Zamasu instantly understood and matched. They raised their hands, bringing the energy ball above their heads, then drew them down together. The ground shattered with destructive force neither could muster alone.
They looked up as one, grinning, hair settling in place in the wake of the shockwave, and it was all Zamasu could do to stop himself from throwing Black into an embrace as when they'd first met.
“Have you wondered how it will feel to fuse?” Black asked after the fight, standing on the deck of their newest temporary home.
Zamasu took a sip of tea and shook his head. His life had seen enough change of late. No need to go out of his way fantasizing about more. “I imagine it won't be any different,” he said anyway. “You are me, after all.”
Black hesitated to reply, and Zamasu soon understood why.
“There is one way to know.”
He meant the other fusion. Metamoran. Certainly they were synchronized enough to manage it, but Zamasu's nose wrinkled at the thought.
“Why stoop to a lesser mimicry of fusion when we alone have access to its true form?” He tipped his head, letting his earring swing and catch the light.
“Our Potara fusion will be permanent,” Black said simply.
“Yes. Permanent, immortal, and undeniable. Are you suggesting we sully it merely to satisfy your curiosity?”
Black at least seemed appropriately affronted. “Certainly not! At any rate, the result of Metamoran fusion would be a different being. If you believed that was enough to set it apart, I could put my qualms aside, but as it is…”
“We are too much the same to disagree on this, Zamasu.”
“Indeed.”
The conversation lapsed into the more casual realm of dinner plans, but the question lingered in Zamasu’s memory. Metamoran fusion was not an option, but there was no closing the box Black had opened. What would their fusion become? He and Black were not identical, no matter what Zamasu had said, but Zamasu couldn't bring himself to be as wary of the differences as he knew Black needed him to be.
There were exactly three reasons Black had sought him out in this timeline. The last and weakest, the one Black would never admit to, was the pleasure of companionship. The second, the only one Black would say aloud, was to be the immortal god the universe needed and Black could no longer be.
But the first and most important reason, known to both but ever unspoken, was to ensure Black’s mortality never corrupted his thoughts. Zamasu couldn’t help but wonder if they’d both underestimated the challenge of the task. They’d had their differences even from the start, forcing Zamasu to guess at which were inevitable, which benign, and which a threat (none as of yet). But the greatest burden—the one Zamasu feared he’d abandoned even before he began—was the need for constant doubt.
Evening came and went. The sky outside was dark and only spotted with clouds, but Zamasu strode onto the deck anyway. Jewels. Black saw the stars as jewels and galaxies as rivers of light, and Zamasu could only wonder where his optimism stemmed from. How could he so easily see a spoiled fruit not for its rot but for the harvest its seeds would grow into? How was Zamasu meant to judge such a soul?
It was too late to simply ask. Black had needed only a lull in the conversation to fall asleep sitting on the couch, his body exhausted after their sparring match. Normally it would be Zamasu's cue to leave, but with one last glower at the sky, he strode back inside, not bothering to turn on the lights.
The sense of otherness had faded since the last time Zamasu caught Black sleeping. The lines of his face shifted over time, same as the rest of his body. They were subtle changes—a slight tension in his brows and cheeks as Son Goku's face adjusted to Black's sharper expressions—but they were enough to bring a smile to Zamasu's eyes. Even if they were to merge now, while Black was still incomplete, time and force of will would be enough to make their new body theirs. Both were resources they had in abundance.
In truth, their appearance was the least of Zamasu's concerns. Or perhaps not concerns, so to speak, but newfound questions. Potara fusion was said to draw upon the best of both participants—their strongest, most defining features combined into a sum greater than both parts. Theirs would no doubt be glorious beyond all others, but what would it take from Zamasu? What beyond his godhood and immortality, traits Black had abandoned and denied respectively, did he have to offer? Everything Zamasu was, Black had already been and moved beyond. Was that a fourth reason Black sought him out? To act as a spare, a holding ground for necessary but unwanted traits?
The thought was almost more flattery than insult. Of all the gods alive and dead, only Zamasu was worthy of fusing with Black, and the reverse was true as well. The space between them was nothing to their height above all others, yet Zamasu was certain the same questions had never occurred to Black. Such doubt was a flaw he no longer suffered from.
It was almost maddening to consider. How, how, even after millennia of enduring Gowasu's teachings, even after taking a mortal form, was his heart so effortlessly pure? How could his every move, from pouring tea to tearing through mortals, come to him with such ease?
It wasn’t a matter of belief. Zamasu’s hatred of mortals was no less bitter if not more so for his extra years studying under Gowasu. But it wasn’t enough. Somewhere along the line, Black’s beliefs had deepened into convictions strong enough to cut through any hesitation. No doubts held him back. No sacrifice was too great—not his body, not the lives of the gods, not even repaying Gowasu's attempted kindness with betrayal. In exchange, every minute of his life was filled with purpose. Every star shone for him. Their fusion would no doubt be the same.
What, then, could Zamasu give in return?
It didn't matter. Not yet. It would be years, decades even, until he fused with Black, and by then, without doubt, he would have more to offer than his body. He was a god. The only pureblooded god left in the multiverse given Zeno's long-held practice of non-interference. It would be Zamasu's opportunity, indeed his duty, to decree the meaning of his divinity and Black's alike. A blade of justice required not only power to wield but direction. Had he not already taken it upon himself to choose the targets of their purge?
If so—if this was to be his path forward—then he truly did belong in the realm of the Kai, gazing down upon the universe as before but willing and able now to descend upon any sinner who caught the ire of his divine will.
Zamasu's place was in the heavens, but his home…
He had time. There were years yet for him to become the god both the universe and Black required of him. The day had indeed been an exhausting one, and after only a moment's hesitation, he lowered himself beside Black on the couch. This too was where he belonged.
As a Kai, Zamasu's body had never demanded much sleep, and true immortality had removed the need for it entirely. It had not, however, dispelled the possibility. If anything, it was easier now, whether from the long interval since his last nap, the deeper darkness of a mortal world at night, or simply Black's gentle breathing at his side. Even half-sitting, half-lying across his half of the couch, it was mere moments until Zamasu drifted away.