They shared a common alignment of interests.
There was another, unspoken reason for his compliance. Through their fist bump, Isobu had seen exactly what Menma knew.
Just like Kurama, Saiken, Chomei, and Matatabi before him, Isobu had formed a deeply 'stubborn' hypothesis regarding Menma's true identity. If that hypothesis proved to be true... forget basic cooperation; they would gladly help Menma unconditionally.
"I understand your intent, Menma. I'm willing to help you, because doing so is helping ourselves," Isobu said, looking at Menma with a deeply serious expression.
Because they had lived for so long, the Tailed Beasts often saw the world far more clearly than any human ever could. The tragedy was that almost no human had ever considered them worth talking to. Even Hashirama Senju—the legendary First Hokage and the world's great 'peacemaker'—had fundamentally treated the beasts as natural disasters to be managed.
His classic, condescending line to the Nine-Tails was proof enough of that.
Madara Uchiha was infinitely worse. He treated the beasts entirely like livestock, viewing them strictly as weapons born to obey his commands. The concept of friendly negotiation never once crossed his mind.
As a result, humans who truly earned the acknowledgment of the Tailed Beasts were incredibly rare. And those few who did usually won them over simply because their personalities clicked.
Menma, however, was fundamentally different.
Not just Isobu, but Kurama, Saiken, Chomei, and Matatabi all clearly understood what Menma was trying to achieve. It wasn't just about neutralizing their mutual enemies. It was about the grand promise Menma had made to them.
Would Menma eventually deceive them? That was a problem for the future. Right now, the catastrophic threat of the Ten-Tails' resurrection was the absolute foundation of their alliance.
Any promises for the future could only be fulfilled if they survived the present.
"Excellent. Thank you, Isobu!"
Even though this was the exact outcome he had anticipated, hearing Isobu's confirmation still brought a bright, genuine smile to Menma's face.
This marked the fifth Tailed Beast joining his ranks.
"So, Menma, how exactly am I coming with you? Are you going to find someone to act as my Jinchuriki?" Isobu tilted his massive head, looking at Menma with curiosity.
Since he had decided to help, they obviously needed to find a suitable human vessel for him. He couldn't exactly waltz alongside Menma in his true, mountainous form. That was practically begging the entire world to attack them.
"No need to wait for anyone else. You can just enter my body, Isobu. Though it'll only be temporary," Menma said with a light chuckle.
He had originally considered bringing Karin along. As a practically flawless inheritor of the Uzumaki bloodline, she could easily serve as the Three-Tails Jinchuriki. Hell, she was durable enough to handle the Nine-Tails if she had to, let alone Isobu.
However, her presence was absolutely vital back in the village. Between the ongoing biological experiments and the heavy administrative burden of merging the Hidden Grass and Hidden Waterfall, Menma simply couldn't afford to pull her away for a ten-day round trip.
Furthermore, Menma's mastery over sealing jutsu and his understanding of chakra had recently reached a new tier. Given his current sealing expertise and his monstrous physical durability, he was absolutely confident he could comfortably house a second Tailed Beast within his own body.
While it was technically a theoretical procedure that no one in history had ever successfully tested... Menma was certain it wouldn't be an issue.
"You? Is that even possible? Isn't Kurama already inside you?"
In his thousand years of existence, Isobu had seen a lot. He possessed a solid understanding of human sealing arts and the physical limitations of the human body. A single human serving as the vessel for two completely different Tailed Beasts simultaneously?
Isobu had never seen or heard of such a thing.
But a second later... recalling the profound hypothesis that had flashed through his mind during their fist bump, a look of sudden realization dawned in Isobu's eyes. He nodded slowly.
"Alright. Cast the jutsu, Menma."
Menma, who was just about to explain his reasoning, blinked in surprise.
Huh? He accepted it just like that?
Seeing the distinct look of realization in Isobu's eyes gave Menma an incredibly bizarre feeling. But deciding not to look a gift horse in the mouth, he didn't question it.
Gesturing for Isobu to move closer to the shore, Menma dropped back down to the ground. Reaching into his jacket, he pulled out several specialized kunai and threw them in a wide arc.
Thud! Thud! They buried themselves into the dirt around him.
Clap! The next second, he slammed his hands together. A massive, violently condensed surge of chakra erupted from his body.
Hum! As Menma's hands blurred through seals, a unique energy pulsed outward. The embedded kunai instantly glowed, projecting layers of black sealing formulas across the ground. Using Menma as the epicenter, the formulas linked together to form three concentric, highly complex arrays.
"Hah!"
With a sharp shout from Menma, blinding light erupted from the seals.
The light was so intense that even Kabuto Yakushi, who was running perimeter security miles away, clearly caught the flash. A strange, awestruck glint flickered in Kabuto's eyes.
He could clearly feel the suffocating wave of chakra from all the way out here.
If Kabuto was shocked, Isobu, who was sitting right at the epicenter, was completely floored. He genuinely hadn't expected this teenager to possess such a boundless, oceanic reserve of personal chakra without even tapping into Kurama's power.
As Menma's chakra peaked at a critical threshold...
"Open!"
Menma threw his arms wide.
The black sealing formulas on the ground instantly came alive, rapidly slithering outward and crawling up Isobu's colossal body. Despite the intense binding sensation, Isobu didn't offer a single ounce of resistance, perfectly cooperating with the jutsu.
Once the black formulas completely encased the beast's body...
"Seal!"
Menma shifted to a final hand sign and spoke the command.
Flash! Space itself seemed to violently contract and expand. Emitting a blinding, radiant light, Isobu's titanic form instantly condensed into a streak of pure energy, rocketing directly into Menma's abdomen.
The light faded.
A second later, the colossal Three-Tails was completely gone from the physical world.
...
Simultaneously, deep within the custom-built mindscape inside Menma's body.
"Hmph. It was already crowded enough in here, and now you drag another one in? You really don't mind asking for trouble, do you, kid?!"
The massive, oppressive metal cage of the original seal was long gone. Resting in the open space, Kurama lifted his colossal fox head from his paws, glaring irritably at Menma and the newly materialized Isobu with a highly displeased expression.
"Hehe, it's just for a few days, Kurama. Don't sweat the small stuff. It's not a big deal," Menma said with a bright, easygoing smile.
Standing off to the side, Isobu looked completely accustomed to this dynamic. He smiled broadly. "It's been a few hundred years, Kurama. I see your personality hasn't changed a bit."
Despite appearing highly familiar with one another, the truth was that the Tailed Beasts rarely actually interacted.
Before the era of Hashirama Senju and Madara Uchiha—when there was almost no one alive capable of forcibly capturing and sealing them—the beasts still hardly ever met up. It was partly because it was inconvenient, and partly because they were simply lazy.
A thousand years was a painfully long time. It was long enough for them to lose interest in the world, and even in each other. Most of the beasts lived in a state of aimless apathy, unsure of what they even wanted out of life.
The only thing anchoring them was the final words of the old man who had treated them like his own children.
It was precisely because of this profound existential exhaustion that the beasts viewed Menma through an entirely different lens. It wasn't about logic; it was simply that he 'felt' different.
"Hehe, exactly! Isobu is totally right. You really need to work on your temper, Kurama."
Suddenly, on the far left of the mindscape, a miniature Saiken popped into existence, sporting an almost human-like, cheeky smile.
"Mm. Kurama, it would be best if you acted a little more grounded."
"Yeah, yeah. Stop being so explosive."
Immediately following Saiken, miniature versions of Chomei the Seven-Tails and Matatabi the Two-Tails materialized in the space.
Because they had previously shared fragments of their chakra with Menma, and due to the innate, telepathic network that existed between the Tailed Beasts, they were able to project these tiny avatars into Menma's mental domain.
"Hmph. You lot are exactly the same. What gives you the right to lecture me?" Kurama snorted indignantly.
"Hehe, that's exactly why we're saying it..."
"If you ask me..."
"You really should..."
Standing below them, Menma watched the incredibly rare, chaotic bickering of the ancient beasts. A deeply warm, gentle light softened his eyes.
Just like Karin, the 'beasts' standing before him were his genuine companions. They were entities he explicitly trusted, especially Kurama.
Even though he had strayed entirely from the golden path walked by the original timeline's protagonist, and they might not share that exact same bond of idealistic friendship, their mutual trust was undeniably just as unbreakable.
Because Menma's resolve was singular, absolute, and unwavering.
"Heh. I'll be relying on all of you moving forward. Our enemies are terrifyingly strong. I hope you'll lend me your strength!" Menma took a deep breath, interrupting the beasts' bickering with a loud, clear voice.
"Oh! Don't worry, Menma. We've got your back!"
"We're fighting for our own survival, after all."
"Hehe, just don't forget your promise to us!"
"Mm!"
"Hmph!"
Hearing Menma's declaration, Saiken, Matatabi, Chomei, and Isobu cheerfully voiced their absolute support. Even Kurama gave a haughty, tsundere snort of agreement.
"There's still Shukaku, Son Goku, Kokuo, and Gyuki. You have to keep pushing forward, Menma," Saiken slithered closer and said softly.
"Yeah. Leave it to me," Menma replied, pumping his right fist with a firm, resounding answer.
It had been an overwhelmingly successful excursion. He had seamlessly secured five out of the nine required targets.
Slowly opening his eyes in the physical world, Menma looked out over the now perfectly quiet lake. A handsome, confident smirk curled the corners of his lips.
"Time to head back."
Looking toward the south, he muttered the words quietly before stomping his right foot.
Swoosh! With an explosive burst of chakra, he vanished completely from the shoreline.
---
Meanwhile, exactly as Menma embarked on his journey home, thousands of miles away in the very heart of the continent.
The Land of Fire. The Hidden Leaf Village.
Inside the Hokage's office, located on the top floor of the iconic administrative building at the center of the world's largest ninja village...
The Fifth Hokage, Tsunade, stared with a solemn, heavy expression at a middle-aged man wearing a dark red shinobi uniform.
Standing flanking her were Jiraiya and Shikaku Nara. Both men watched the envoy with strange, calculating glints in their eyes.
The middle-aged man standing opposite them appeared completely relaxed, radiating an aura of total composure.
"Well, Lord Hokage? These are the absolute best terms we can offer. As long as you agree to them, all subsequent details will be highly negotiable," the man said with a polite smile, meeting Tsunade's gaze without flinching.
"Hmph. Now you want to talk? Where was this so-called 'sincerity' before? Yes, the terms certainly look generous on paper. But give me one good reason why I should trust the Hidden Stone... Kamizuru Iwazetsu," Tsunade sneered, her face laced with profound distrust.
While the Leaf had engaged in two or three preliminary diplomatic exchanges with the Stone prior to today, they had all been surface-level political theater. It wasn't until this man arrived—a high-ranking Stone Jonin and the renowned head of the Kamizuru Clan, Iwazetsu—that the negotiations finally dug into the real meat.
He had clearly been granted full plenary authority by the Third Tsuchikage. And the cooperative terms he brought to the table genuinely looked incredibly favorable for the Leaf.
But Tsunade had every reason in the world to heavily suspect the Hidden Stone's true motives.
"Heh. Please rest assured, Lord Hokage. Our village comes bearing absolute sincerity. If your esteemed village agrees to our terms, the Hidden Stone is willing to be the first to launch military operations. How does that sound? Surely that is enough to earn your trust?"
Completely unfazed by Tsunade's hostile attitude, Iwazetsu maintained his calm, collected demeanor as he delivered his final pitch.