As the second Jinchuriki of the Nine-Tails chosen by Konoha, Kushina's safety was of paramount importance. Especially now, with Uzumaki Mito growing older.
That was why Hiruzen Sarutobi came up with the idea of having her team up with Aoshi.
Coincidentally, Aoshi also didn't have any teammates to register with, and the two of them were already good friends, making them an ideal match.
More importantly, with Aoshi's strength, he could absolutely ensure Kushina's protection.
"Alright, alright, I got it. I'll let Kushina know tomorrow. If there's nothing else, I'm going to rest." Seeing Tsunade's impatient tone, Hiruzen could only shake his head with a helpless sigh.
Still, it was quite late—he too should be heading home.
---
After escorting Mikoto back to the Uchiha Clan compound, Aoshi returned straight to his own home.
Without delay, he eagerly performed a summoning jutsu, summoning a tiny slug no larger than his palm.
"Aoshi-sama, it's quite late. Is something the matter?"
"Great Slug Sage, I heard that the Three Great Sage Regions each possess a unique form of training known as Sage Arts?"
That was precisely why Aoshi summoned the Great Slug despite the hour—his desire to grow stronger burned too fiercely.
"So Aoshi-sama wishes to study Sage Arts? With your current chakra reserves, it would just barely be feasible."
The Great Slug didn't reject him; it simply offered an honest assessment.
Hearing this, Aoshi fell silent for a moment. He currently possessed nearly 80,000 units of chakra, already far exceeding most shinobi in the world.
And yet, in the Slug Sage's eyes, that was just barely enough to qualify for Sage training? No wonder so few had ever succeeded in learning Sage Mode throughout history.
The chakra requirement alone eliminated 99% of all ninja.
Of course, this wasn't because the Great Slug was being overly selective—it was simply that attempting to learn Sage Arts without enough chakra was extremely dangerous.
The natural energy in the shinobi world was highly corrosive. Without sufficient chakra, one could be quickly overwhelmed by nature energy and dissolved—becoming one with the earth itself.
"So, Great Slug Sage, how exactly does one train in Sage Arts?"
Most of what was known about Sage training came from Mount Myoboku, home to Jiraiya, Minato, and Naruto—all of whom studied Sage Mode there.
Second was Ryuchi Cave, where Kabuto Yakushi learned Sage Mode from White Snake Sage, and where Orochimaru once trained but ultimately failed.
As for Shikkotsu Forest, the details had always been vague. No one knew how one was trained there, or who—if anyone—had succeeded.
Some speculated that Hashirama Senju's Sage powers originated from Shikkotsu Forest, but no solid evidence supported the claim.
"It's quite simple, really. If you can withstand my acidic mucus, you'll be able to learn Sage Arts." Despite the gentle, adorable voice, the words sent a chill down Aoshi's spine.
The Slug Sage's acid was famously corrosive—one of its rare offensive abilities. How could a human body possibly endure something like that?
"Great Slug Sage… has anyone actually learned Sage Mode that way before?"
The Great Slug paused to recall. "If I remember correctly, a few hundred years ago, someone succeeded. He had an extraordinarily strong body and regenerative ability."
Aoshi was completely speechless. Compared to Mount Myoboku and Ryuchi Cave, Shikkotsu Forest's Sage training sounded dozens of times more dangerous.
It was practically suicide.
Suddenly, Aoshi had a realization.
The word "bone" in Shikkotsu Forest… could it be that those were the remains of those who had failed Sage training, their bones piled up like a forest?
Just like the failed trainees at Mount Myoboku, who all turned to stone.
No wonder Tsunade never learned Sage Mode in the original story. In her youth, she hadn't developed the Yin Seal or the Ninja Art Creation Rebirth — Strength of a Hundred Healing, so she naturally couldn't train in Shikkotsu Forest.
By the time she had mastered the Ninja Art Creation Rebirth — Strength of a Hundred Healing, she had already left Konoha and was wandering the world, gambling and drowning in debt.
She hardly had the mindset to train in Sage Arts. Even when she returned to Konoha as Hokage, brought back by Jiraiya and Naruto, her schedule left her with no time for Sage training.
Of course, it was also possible that, like Orochimaru, Tsunade simply lacked talent in Sage Arts altogether.
"So, Aoshi-sama, do you still wish to pursue Sage training?" That soft voice now sounded like the call of death itself.
Frightened, Aoshi quickly replied, "I just wanted to understand Sage Arts better. I'm not planning to train in them just yet."
Though he could sense nature energy, there was no way he'd survive that kind of training. For the sake of staying alive, he had no choice but to decline.
"Of course! If Aoshi-sama ever wants to learn more, feel free to ask me anything."
"Then, Great Slug Sage, may I ask how you personally came to master Sage Arts?"
Aoshi had initially thought he could easily learn Sage Arts in Shikkotsu Forest. But now he realized that was wishful thinking.
He figured that researching Sage Arts on his own might actually be a safer route than formally training in the forest. So, the best course was to ask the Slug Sage as many questions as possible.
After all, Sage Arts weren't something that could be grasped just by knowing the theory. Otherwise, someone as brilliant as Orochimaru would've mastered them already.
"No problem at all." The Great Slug Sage then began patiently explaining how it had learned Sage Arts from scratch.
Throughout the conversation, it also answered Aoshi's many questions in great detail. Unknowingly, dawn had already begun to break.
"Thank you, Great Slug Sage."
"You're welcome. If you ever need help again, just summon me."
With that, the Sage canceled the summoning technique and returned to Shikkotsu Forest.
A full night had passed, and Aoshi had gained valuable insights—he now had a clear path forward for his Sage research.
"Guess I'd better head to the Konoha Hospital." Even though he hadn't slept, for a ninja, skipping one night of rest wasn't a big deal.
Sometimes, missions could demand several sleepless days in a row.
"Ah! Aoshi-sama, you're finally back!"
"It's been so long! Welcome back, Aoshi-sama!"
The nurses at Konoha Hospital were thrilled to see him again after more than half a month.
"It's good to see you all, too." After greeting them, Aoshi returned to his office and took out a scroll to begin documenting his ideas for Sage Arts research.
Just then, a nurse knocked on his office door. "Aoshi-sama, there's a patient who needs immediate treatment."
Aoshi immediately put the scroll away. "Understood. Prep for surgery—I'll be there right away."
[You have successfully treated Seitaro Tanabe. Reward: 1 Blue Orb.]
[Congratulations! You have gained 100 chakra points.]