[A/N: update schedule would be all over the place for the following few weeks. I can't update daily due to having sleep troubles. I'm sleepy all of the time and can't fall asleep.]
With those final words, Sinbad raised a hand, and the summoning was undone. The Gedo Statue vanished in a flash of unnatural light, drawn back to the moon from which it came. In its absence, the battlefield grew quiet, the air heavy with disbelief, as if the world itself was catching its breath.
Without another word, Sinbad turned away and drifted calmly through the air, his expression unreadable. He left the rest to them.
And with that, Fugaku stepped forward, his eyes spinning with power. Sharingan flared, locking with the wild, raging gaze of the 9 Tails. In a heartbeat, its movements slowed, then stopped altogether, caught within the web of genjutsu as Fugaku took control.
Sinbad turned his gaze toward the distant battlefield, where Minato was locked in combat with the Six Paths of Pain and Obito. As expected, Minato was on the losing end, forced to remain on the defensive. The combined abilities of Pain and Obito constantly kept him off-balance, forcing him to move with precision just to stay alive. But even so, Minato wasn't fighting to win. He was testing the waters, probing their strength, and as always, proving far too slippery to pin down.
Still, with the Gedo Statue and the Nine Tails no longer under their command, Pain and Obito had no choice but to retreat. Their greatest weapons had slipped from their grasp, and they weren't prepared for a prolonged fight without them.
With the threat momentarily passed, Minato wasted no time. He moved swiftly to seal the Nine Tails back into Kushina, saving her life in the process. A small part of him hesitated, briefly considering what Sinbad had said about Naruto. But in the end, he chose differently. There was no need for the Reaper Death Seal—not this time.
The next morning, Minato arrived alongside several elders of the Hidden Leaf to personally thank Sinbad. Their gratitude was clear—without Sinbad's intervention, Minato was certain he would've had no choice but to use the Reaper Death Seal, dooming himself and placing the burden of the Nine Tails on his newborn son.
But Sinbad remained unmoved. He listened politely, offered a few nods, but otherwise didn't dwell on the praise. To him, he was merely a guest in their village, and it was only right that a guest repay kindness with a small act of goodwill. That was all it was to him.
And even with all that had happened, even with the paths he knew he would walk in the future—paths many might see as dark or cruel—Sinbad still held to his faith. At heart, he was still a Christian, even if the world might soon call him something else entirely.
***
Well, time passed, and Sinbad spent most of his days exploring the Hidden Leaf Village, taking in its layout, its people, and the subtle patterns of shinobi life. A close second to that was the time he dedicated to teaching Itachi. As for why? There were two reasons he'd taken up the role of teacher.
First, Itachi had personally asked him—something rare for someone her age, but her sharp eyes and composed nature made it clear she was anything but ordinary. Second, Sinbad had been entertaining the thought of creating his own jutsu, techniques that would go beyond the limits of what the shinobi world had ever seen. Just because he had already mastered every known jutsu didn't mean there wasn't another level to reach—one he could carve out himself.
That spark of inspiration had come from Itachi herself. One evening, Fugaku and his family visited Sinbad, and he welcomed them warmly, hosting them in the old estate he'd been given. Over the course of the meal, Sinbad had voiced a frustration—he wanted to get stronger, but nothing available at the moment seemed capable of pushing him any further.
Itachi had tilted her head and asked a simple question: why couldn't he just create his own jutsu?
And just like that, something clicked. A new door had opened. Sinbad had spent so long mastering what already existed… he had never truly considered creating something entirely new.
He had been wasting time—waiting on the system to grant him stronger abilities—when he could've been creating his own jutsu to increase the odds of drawing more powerful skills. It was a simple thought, yet one he hadn't reached on his own. If not for Itachi, Sinbad honestly didn't know how long it would've taken him to consider such a thing. After all, no one can think of everything, not even someone like him. That was one of the reasons he agreed to teach her.
There was another reason, of course, but that first one held the most weight.
"Today is the seventh day. Are you leaving?" Fugaku asked, seated beside Sinbad, who was quietly watching Itachi as she trained with unwavering focus.
"Yeah, I'll be leaving in a few minutes. I don't know when I'll return—maybe in a few weeks, or at most a year—but it won't be long. I'll come back with the capability I need," Sinbad said lightly, his focus shifting inward as he sensed [World Gate]. Its cooldown was nearly over, the time ticking down toward zero.
"Well, I'd like to thank you again," Fugaku said with a calm sincerity, his gaze falling on Itachi as she trained in the distance. "If it weren't for you, I'm sure the Uchiha clan would've been blamed. And without Minato, we might've been pushed into a corner with no way out. I don't know if I'll ever be able to repay you."
Sinbad had warned him of what could happen—had told him what Itachi was capable of doing. And Fugaku, as her father, knew her well enough to believe that the future wasn't out of reach… not if someone like Sinbad wasn't there to keep it from unfolding.
"It's not a big deal…" Sinbad said lightly, rising to his feet and walking forward. As he moved, a shimmering portal opened before him, warping the air around it with a quiet hum. The sudden shift drew Itachi's attention, causing her to pause mid-movement, her eyes fixed on the sight with quiet curiosity.
"I'll see you guys soon." With those parting words, Sinbad stepped into the swirling light, vanishing from the Shinobi world without hesitation.
Itachi continued staring at the space where he had just stood. Her breath left her in a slow exhale, eyes sharpening with renewed focus. A quiet but fierce resolve bloomed in her chest—to grow stronger, and to bring peace to this world in her own way. That goal was the other reason Sinbad had agreed to teach her. She understood something most didn't: without strength, peace was only a fleeting dream.
***
Sinbad appeared in what seemed to be a vast desert, where a gathering had formed. The atmosphere was tense, all eyes focused on a single figure—Frieza, whose once-pristine body had been partially replaced with advanced robotic parts. But not everyone was standing toe-to-toe with Frieza and his father. That honor belonged solely to Future Trunks.
At the moment of Sinbad's arrival, everyone sensed him. Though he didn't possess Ki in the traditional sense, what pulsed from him was strikingly similar—dense, concentrated, and filled with overwhelming pressure. His presence alone was enough to draw attention. Compared to the version of Goku who had once defeated Frieza and left him in his current condition, Sinbad stood on equal footing. His aura, alien though it was, radiated power that couldn't be ignored.
"Who are you?" Frieza asked, his frown deepening as he studied Sinbad. At first glance, Sinbad looked painfully ordinary. He had simple black hair, and while not unattractive, he wasn't particularly handsome—just slightly above average. He stood at six feet, with nothing remarkable about his appearance. To anyone else, he would've looked like a harmless human. But his aura told a very different story.
"I don't like you," Sinbad said bluntly.
In an instant, he vanished, reappearing directly in front of Frieza. The sudden teleportation caught Frieza completely off guard. He didn't even have time to react before a truth-seeking orb materialized and pierced clean through his head, reducing it to dust.
With a single thought, Sinbad opened all eight gates, and his aura erupted like a storm. His power skyrocketed, surging to terrifying new heights. His heart pounded at its absolute limit, each beat thundering through his chest with such force that, under normal circumstances, a human's blood would boil, the pressure forcing a mist of red to escape their skin and form an aura of blood around them. But Sinbad's regeneration was far too fast—his body simply couldn't be broken.
"Big Bang Fist!" he roared as his fist rocketed forward, meeting King Frost's punch mid-air.
The moment their fists collided, a deafening shockwave erupted outward. It wasn't just a blast—it was a cataclysm. The earth trembled violently beneath them as if struck by something far worse than a nuclear bomb. The resulting earthquake wasn't contained to the region; it rippled across the globe, leaving the entire world trembling in the wake of their power.
King Frost, for all his strength and terrifying power, was nothing before such overwhelming force. Sinbad's fist—infused with Conqueror's Haki, Armament Haki, and countless jutsu—landed with finality. It wasn't just a strike. It was a verdict.
King Frost was one-shotted, his body shattered into nothing, along with the massive ship he'd arrived in and the entire army that followed him. All of it… erased in a blink. Not even ashes remained.
Sinbad exhaled, slowly closing all eight gates as his aura faded. His body returned to normal, calm once again, as if nothing had happened.
"Who are you?" Trunks asked, stunned beyond words as he stared at the man who had just ended a nightmare in one blow.
"I'm Sinbad, and I came to help you guys with the androids," Sinbad said with a light smile, leaving Trunks stunned and unsure of what to make of it all.
"Goku, you can show up now," Sinbad added calmly, his eyes turning toward the sky. His voice carried no power outward, yet his words weren't meant for anyone here to hear. They traveled light years across space, a direct message sent through sheer will, meant only for Goku.
After a second, Goku suddenly appeared on Earth, teleporting in with his usual ease. The moment he arrived, the entire crowd erupted into cheers, their spirits lifted at the sight of their strongest hero.
"W-what?" Trunks stammered, completely taken aback. He couldn't comprehend how Goku had shown up out of nowhere like that, without any warning or buildup.
Without wasting time, Sinbad gently grabbed both Trunks and Goku by the shoulder and pulled them aside, leading them away from the crowd so they could speak in private.
"I'm from a different universe. I mainly came here to train with one of the greatest warriors out there," Sinbad said with a calm smile, stunning both Goku and Trunks with how casually he revealed such a thing.
"I'm from the future," Trunks added lightly, steadying his tone before continuing. "I came back in time to prevent my future from happening."
He then explained everything. Two powerful and merciless androids would soon be created—monsters that wiped out nearly all the Z-Fighters. Worse, Goku wouldn't be around to help them. He would die from a rare heart virus before the real battle even began, leaving the others hopeless. One by one, they were hunted down and killed, until only Trunks remained. That was why he came—both to deliver a warning and to give Goku the cure for the virus that would soon take his life.
"I wouldn't be around for the battle against the androids, since I'll be leaving next week. But in the meantime, I want to do my best to help you all grow stronger, which, in return, would help me grow stronger too," Sinbad said with a relaxed smile, his tone light but sincere.
"You seem to have a weird Ki… what's that about?" Goku asked curiously, tilting his head slightly as he studied Sinbad.
"My world doesn't have Ki. Instead, we use Chakra—the fusion of spiritual and physical energy," Sinbad explained, his gaze calm and thoughtful. "On that note, can you give me some Ki so I can also gain it?"
Goku nodded without hesitation, raising his hand and letting his energy flow into Sinbad. The transfer was smooth, but the moment Sinbad felt the foreign energy enter him, he looked down at his palm.
He could already sense his body adapting. Slowly, the Six Paths Sage Chakra within him began to shift, twisting and merging with the foreign Ki. The result wasn't just compatibility—it was fusion, creating something entirely new. Something far more powerful.
"Thanks. I don't know if you can also gain chakra, but I don't mind giving it to you to see," Sinbad said calmly, extending his hand as he passed on a portion of his normal chakra. He made sure not to share his Six Paths chakra—after all, not just anyone could handle that and walk away unharmed.
Goku's eyes widened almost instantly. "Wow…" he muttered, a mix of awe and surprise in his voice as he felt the surge within. His power spiked dramatically, increasing by nearly fivefold.
Sinbad observed this with a faint nod, watching Goku process the change, before finally speaking again.
"Can you use the Kaio-Ken? I think I should be able to copy any technique you show," Sinbad said casually, his voice confident but calm. His words left Goku stunned for a moment—clearly, he didn't quite believe such a thing was possible. Still, Goku nodded and took a step back.
He exhaled slowly, then his body tensed. "My former limit for the Kaio-Ken was twenty. That was the peak of what my body could ever handle, no matter how much I trained…" Goku said, clenching his fist tightly as a red aura began to spark around him. Then, with a shout that carried both power and pride, he called out, "Kaio-Ken times forty!"