"What didn't Lady Tsunade want me to find out?" Sakura asked eagerly. "Does it have something to do with Sage stuff?"
For a ten-thousand-metre-tall slug monster, Lady Katsuyu certainly cut a sorry figure.
"Hawawaa…" whimpered Micro-Katsuyu pitifully. "You do have a right to know as my summoner, but… Lady Tsunade asked me not to say anything…"
For some reason, Katsuyu treated Tsunade with an abnormal amount of respect, which was something that had always puzzled Sakura. It was completely at odds with how the top figures of Ryūchi Cave and Mt Myōboku treated their contractors.
For example, the Prophet Gamamaru, the Great Honourable Geezer—er… I mean, the Great Toad Sage— had to be treated with the utmost respect by the lesser toads, as well as by Naruto and Jiraiya. The same went for the White Snake Sage and the three Snake Princesses— though showing respect wouldn't necessarily guarantee they wouldn't gobble you up whole.
"Why don't you start by telling me what it is I'm not supposed to know?" Sakura suggested. "If it's really that dangerous, I'll just pretend I didn't hear a thing. It'll be our little secret."
"You won't tell Lady Tsunade?" asked Micro-Katsuyu hopefully. "I don't want her to be mad at me…"
Sakura nodded vigorously.
"In that case, I don't mind sharing what I know," said Micro-Katsuyu spiritedly. "Let's see, where to begin… Why don't you start by moulding some chakra, Sakura-san? By perching on your shoulder, I've connected myself to your chakra pathway network, so I'll be able to teach you more effectively."
Extracting chakra from the trillions of cells in her body had become second nature to Sakura, but putting the process into words was still incredibly difficult. It was like a bird trying to explain to a fish what it felt like to fly— without the right organs, true understanding was impossible.
The best explanation Sakura could come up with is something like this: extracting chakra is like clenching an imaginary muscle to squirt out stamina juice, and then spinning that with concentration power— converting the intangible into something tangible!
"Very well done, Sakura-san," hummed Katsuyu. "A nearly fifty-fifty ratio of physical and spiritual energies with negligible losses."
Sakura stuck out her prodigious chest proudly.
Even the most seasoned shinobi couldn't match her efficiency when it came to extracting chakra! Naruto couldn't even get close to a perfect fifty-fifty split…
"And that's exactly why humans that are good at kneading chakra are no good at moulding Senjutsu chakra," said Micro-Katsuyu sadly, shaking her little head. "…ah, I suppose I should tell you about Senjutsu first…"
"Eh?" hiccupped Sakura.
"You've felt it before, haven't you? Nature Energy, I mean," Micro-Katsuyu said softly. "I can still sense faint traces inside you. You're very lucky it didn't overwhelm you. In a way… maybe it's a good thing you're learning about it now."
By this point, Sakura had already absorbed Natural Energy a few times— either by stealing breasts from a Cursed Seal holder, or by absorbing it directly from a Stone of Gelel composed of pure, crystallised Life Energy.
"Now that I've stopped moving around, I can definitely sense there's something different about the air around here," said Sakura, closing her eyes. "Is that Natural Energy?"
"Whatever you do, you mustn't try to absorb it," said Micro-Katsuyu warningly. "If you do, I'll have no way to force it out of you."
"I wasn't going to!" Sakura protested.
The System had been beeping nonstop for a while now, warning her about the dangerous radiation permeating the area. It was getting kind of annoying, actually.
"To answer your initial question, Sages are those who have mastered the use of Senjutsu chakra," began Micro-Katsuyu. "It's a far more potent form of chakra, with much greater staying power thanks to the input of Natural Energy— it lingers in the body far longer before dissipating. That's why hosting it within one's body is called Sage Mode."
As long as Sage Mode was active, there was no need to extract chakra— it was already present in the body. Senjutsu chakra only needed to be moulded, streamlining the Jutsu-casting process considerably. Moreover, simply having Senjutsu chakra circulating through one's chakra network greatly enhanced the five senses, along with one's strength, speed, Ninjutsu, Genjutsu, and Taijutsu.
"Regular chakra is a 1:1 ratio of spiritual and physical energies," she continued. "Senjutsu chakra, on the other hand, is a balanced 1:1:1 blend of spiritual, physical, and natural energy— and therein lies the rub."
No matter where they live, humans will have ten fingers (barring any unfortunate accidents), and so, they will naturally prefer counting with ten digits: 0 through 9— whether they use the base 10 decimal system (for those endowed with common sense) or the base 12 imperial system (for those who like to divide things by three or four).
Sakura had no trouble picturing fifty percent of something, but trying to visualise exactly thirty-three point three three three three three three three (and so on) percent? That was hard!
'No wonder Naruto got the hang of it so easily!' said Inner Sakura despairingly. 'He's got so much stamina he never bothered training to make the 1:1 ratio an automatic reflex, so he had no trouble unlearning the habit to switch to 1:1:1!'
"What happens if I take in too much Natural Energy?" asked Sakura timidly. "You said you wouldn't be able to expel it from my body…"
"You'll turn into a slug and become a part of me!" said Micro-Katsuyu happily. "How do you think I got so big?"
Sakura's jaw dropped open—didn't that mean she only had one shot to get it right, just like with the snakes of Ryūchi Cave!? She knew those who trained with the toads and failed to balance their energies would first turn into toads and then into stone, but to think… wait, hold on!
"Don't tell me you used to be human, Lady Katsuyu?" asked Sakura tentatively.
"I used to be plenty of humans," said Micro-Katsuyu wistfully. "Do you wish to hear my story?"
Dumbfounded, Sakura nodded.
"A long, long time ago," recounted Micro-Katsuyu, "well before the Box of Ultimate Bliss was unearthed in the Land of Grass, long before the withering of the God Tree and before the birth of the Sage of Six Paths, a certain Otherworldly Demon appeared in the country now known as the Land of Demons…"
Sakura's head spun. Apart from the canon stuff, this was the first time she was hearing any of these big names!
"Humanity came together to stop the demon— but this was long before the advent of chakra, so the vast majority of humans were powerless against the dread Mōryō," continued Micro-Katsuyu. "Only we sages had the strength to hold it back, even if only temporarily, buying time for the sacred priestess to prepare her sealing spell."
'Spell?' pointed out Inner Sakura. 'Not Jutsu?'
"One most hold perfectly still in order to absorb Natural Energy, which is why I designed the Yin Seal in the first place— to replenish my Senjutsu chakra in combat," sighed Micro-Katsuyu. "But the battle against the immortal demon dragged on longer than any of us had anticipated, and we were forced to draw upon energy we didn't possess. The toads, the snakes, my clan… on that day, we all ceased to be human, but at least, we saved the world..."
From then on, Mōryō would manage to break free from his seal a few more times— but by that point, humanity had gained chakra, making it significantly easier to beat him back into his hole.
"Katsuyu-sama…" said Sakura hesitantly.
"Due to the Yin Seal's uniqueness, my clansmen and I were merged into one, unlike the other Sages," Katsuyu finished quietly. "With our minds shattered, we slithered back to our home in Shikkotsu Forest, broken and lost. We remained that way, wandering aimlessly for thousands of years… until a young Lady Tsunade stumbled into our sanctuary— and somehow, managed to piece us back together."
Without realising it, Sakura had been holding her breath while listening to the epic tale.
"Medetashi, medetashi!" sang Micro-Katsuyu joyously, wiggling her eyestalks. "And all is well that ends well. Did you enjoy my tale, Sakura-san?"
"I think I'll hold off on learning Sage Mode just a bit longer," groaned Sakura. "Maybe once I've got more chakra…"
It had been a while since she had checked her System Panel…