Fifteen minutes later, Uchiha Ran and Tsunade, moving at full speed, reached the foot of the mountain and began their ascent to the summit. Before long, a colossal form came into view — the immense body of Katsuyu.
"Is that the Katsuyu of the Sannin?" Uchiha Ran asked in awe, staring at the enormous creature, which towered dozens of meters high even while lying down.
"No," Tsunade shook her head. "That's only a part of Katsuyu. Her primary consciousness resides in that portion."
"No one has ever seen Katsuyu in her entirety."
"Uh…" Ran gave her a peculiar look, still stunned by what he'd heard.
Who was it again, boasting during a battle that they could summon a tenth of Katsuyu?
But in reality, you can't even summon a tenth of this "small fragment", right?
Ran had felt something off from the start.
Katsuyu was one of the legendary Sannin, on par with the White Snake Sannin and Gamamaru.
Compared to her, Manda and Gamabunta were practically mutts. Putting them in the same league was a joke.
Even a tenth of the real Katsuyu should've been enough to crush Manda or Gamabunta without breaking a sweat. But the summoned fragment hadn't shown anything particularly overwhelming. Nothing befitting a creature of her title.
Now that it was clear this was merely a sliver of a sliver — everything finally made sense.
Good thing Ran already knew about Katsuyu's gentle nature. Otherwise, the moment he saw her mountain-sized form, he might've just dropped dead from fright.
They kept climbing up the slope, and Ran felt a sense of relief — the higher they went, the weaker the effect of the caustic fumes became.
By the time they reached the peak, the air felt nearly normal.
"Welcome, Uchiha Ran," Katsuyu spoke first, with no arrogance in her voice — it was soft and drawn out. "You seek to learn senjutsu?"
"An honor to meet you, Katsuyu-sama. I really can learn it?" Ran replied with excitement, encouraged by her taking the initiative.
Instead of answering, Katsuyu opened her mouth wide and swallowed him whole.
Ran didn't panic in the slightest. The moment he was inside her body, it felt as if he had been transported to another realm altogether.
Natural energy began surging in from all directions, washing over him like a waterfall.
Closing his eyes, Ran focused deeply.
To his amazement, the energy blended with his body naturally and effortlessly.
Entranced, Ran cautiously guided a thread-thin stream of natural energy into himself.
Carefully balancing it with his physical and spiritual chakra, he suddenly felt something new stirring — the birth of senjutsu chakra inside him.
It was just a speck — but the process felt completely seamless.
This was Uchiha Ran's own innate ability, not something inherited from Senju Tobirama.
And that realization filled him with indescribable joy.
He'd never imagined he possessed such a talent.
When Katsuyu finally spat him out, she gave a satisfied nod.
"I can sense it. Your natural affinity for senjutsu is very strong. You're well suited to learning Shikkotsurin-style senjutsu."
"You...!" Tsunade flinched as the words left Katsuyu's mouth. A pang of bitter frustration hit her — too intense for words.
She herself didn't have even the faintest aptitude for senjutsu — and it had always been her greatest regret.
Not that she'd been too hung up on it before.
Shikkotsurin senjutsu was said to be the most difficult among the three sacred grounds. Of all the people she'd known, only Senju Hashirama had ever mastered it.
And now — this guy could too?
"What the hell?!"
Still, Tsunade felt genuine happiness.
After all, she had been the one to ask Katsuyu to teach Ran.
No matter how painful the comparison, deep down, she was sincerely glad.
Because what mattered most now was that Ran gained true strength.
So he would never again stand on the brink of death.
Learning senjutsu meant he would finally possess a real means of self-defense. And soon, he'd be able to live openly in Konoha.
Hashirama's life had taught her: when your power is great enough, no law can hold you back.
Those with true power make the rules — and others follow them.
The day would come when Uchiha Ran would make the rules. And when that day arrived, who in Konoha would dare stand against him?
Suppressing the bitterness that had built up over seven long years, Uchiha Ran finally set foot on his own path to strength.
And the one who would guide him — was Tsunade.
For the next month, every night, Uchiha Ran used Reverse Summoning to return to Shikkotsurin.
The method was simple: Tsunade summoned a small fragment of Katsuyu, relayed the request, and the Sannin performed the reverse summoning to bring them both to Shikkotsurin.
To return, they used a method similar to the one Naruto had used during his battle with Pain — when his clone in Myōboku summoned the real him back to Konoha:
Each left a clone at home, and at a predetermined time, the clone would use a summoning scroll to call them back.
During this time, while listening to Tsunade's explanations on ninjutsu principles and battle techniques, Ran also:
Mastered the Technique of Monstrous Strength,
Refined and perfected the jutsu he'd already learned,
And trained diligently in Shikkotsurin-style senjutsu.
His days were absolutely packed.
On the summit of one of Shikkotsurin's peaks—
Uchiha Ran retreated rapidly, dodging Tsunade's blows while weaving hand signs at blinding speed:
Mi — Hitsuji — Saru — I — Uma — Tora!
(Snake — Ram — Monkey — Boar — Horse — Tiger)
He performed the six seals in the blink of an eye, his hands moving too fast to follow.
Then he drew a deep breath, arching back, his chest swelling as if to swallow all the surrounding air.
Chakra whirled violently within him as fire nature chakra surged in his throat.
A second later, a massive wave of flame burst from his mouth, forming a giant fireball hurtling straight toward Tsunade.
The air rippled from the heat, crackling and roaring as the fireball rushed forward.
Katon: Gōkakyū no Jutsu.
But Tsunade had already sensed the incoming attack.
With a powerful stomp of her right foot, the ground cracked beneath her and massive chunks of rock flew into the air.
As the fireball neared, her foot flared with blue chakra — and she kicked one of the largest slabs.
But rather than shatter, the slab soared forward, launched like a cannonball by the sheer force of the kick, straight toward the oncoming fireball.
Using the recoil, Tsunade dropped low to the ground in a flash.
And just as her feet touched the earth, she tapped it gently with chakra-coated fingertips — and her body shot upward like a released catapult, chasing after the flying boulder.
Amazingly, the ground remained untouched.
Monstrous Strength Technique: Precision Control Mode.
This was a new jutsu Tsunade had developed after years of training, inspired by Uchiha Ran and guided by the teachings of her grandfather and great-uncle.
An evolution of her original Monstrous Strength Technique.
Before, any of her attacks would cause massive collateral damage.
Now, in Precision Control Mode, she could gather all her power internally without losing a single drop — keeping it fully contained.
Thanks to this extreme concentration, her speed reached terrifying levels — like a hypercharged version of the Body Flicker Technique.
In this mode, Tsunade combined:
Absolute movement speed,
Devastating instant power and destruction,
And top-tier physical regeneration.
She no longer needed flashy or drawn-out techniques.
All of this happened in an instant.
From the outside, the scene looked like this:
A massive boulder sliced through the fireball, while behind it, cloaked in the shadow of the flames, Tsunade surged forward — barely skimming past the burning heat.