"A bit of chakra?! Just a bit?!"
Satoru wanted to curse. Sarutobi Sasuke had Super-Kage chakra reserves, plus Gold and Silver Horns'—who killed a Raikage and nearly killed a Hokage! Add the Previous Monkey King's, and the total far exceeded his own several times over. Factoring in the Nine-Tails'—over a hundred times!
"Absorb all that... When the hell would that end, in what monkey year and horse month?!" Satoru nearly exploded in profanity, but then he remembered the System.
"System! System, you there?! Any way to absorb this chakra?" he thought.
The System replied soon enough.
"Want to absorb chakra? Piece of cake!" The System's voice dripped contempt.
"Piece of cake? How? If I start now, won't it rip me apart?" Satoru asked.
"Forgot? You ate a weakened Chakra Fruit, and you're an Indra bloodline carrier. Absorbing some Tailed Beast chakra is trivial," the System stated. "You're too small to use it all directly now, but you can use sealing to store what you can't use yet."
"Seal the chakra? Ask Sarutobi Sasuke?" the youth clarified.
"That guy's just a chakra imprint—he can't help. Remember who in 'Naruto' could store unused chakra?" the System prompted.
"You mean Tsunade? Yin Seal?" Satoru caught on.
"Right. You have two lottery attempts left. Sacrifice both for Yin Seal mastery. Then you can handle this chakra temporarily!" the System offered.
"You rip-off! I beat the Nine-Tails and Sarutobi Sasuke, and you give just two tries? Too stingy!" the young Uchiha fumed.
"You didn't fully beat the Nine-Tails. Gold and Silver Horns ate his flesh and blood, with Sage of Six Paths physique—that's why you lucked out. Previous Monkey King was sealed, couldn't use full power. Two tries is generous. Exchange for Yin Seal?" The System sounded impatient.
Satoru didn't want to anger the System—and truthfully, she was right.
"Fine! Exchanging!" Instantly, he mastered Tsunade's Yin Seal.
Sarutobi Sasuke, watching the youth, sensed something had changed in him.
"Ready to absorb chakra? When you're ready, say so, and we'll all enter your body," the ancestor of Hiruzen said.
"Don't phrase it so disgustingly... Wait a bit, I need to prepare one more ninjutsu," Satoru said. Naturally, preparing to absorb chakra a hundred times greater than his own, he wanted to prepare thoroughly.
"Actually, you don't have to absorb all this chakra right now. You can first absorb the chakra of the Previous Monkey King, mine, and the chakra of the Gold Horn and Silver Horn. Absorb the remaining Nine-Tails chakra next time. After all, you're still too young. Absorb it gradually, and when you grow up, come back and take the rest."
"This is the Sage's final trial. Pass it, and you'll be able to learn senjutsu surpassing the techniques of the Three Great Lands of the Sages! But you're still young, and you have plenty of time, right?" Sarutobi Sasuke said.
"Got it, got it, shut up," Satoru said. He wasn't in the mood for this right now. Since he'd exchanged attempts for the Yin Seal, he naturally had to master it.
He began carefully studying and preparing the Yin Seal. He didn't know how much time passed, but finally Satoru was ready.
"Yin Seal Technique!" Applying it, the young man addressed Sasuke's spirit: "Done. All the chakra except the Nine-Tails' can enter."
"You're ready? Then we're coming!" Sarutobi Sasuke exclaimed.
"Wait, what will happen to the Nine-Tails' chakra after I absorb yours?" Satoru asked.
"Don't worry, his chakra can't leave this well. When you want to absorb it, just come back here," the Sarutobi clan ancestor replied.
"Alright, then let's begin," Sarutobi Sasuke nodded, placed his hand on Satoru's stomach, and in the next instant vanished with a whoosh.
"Khh!" Satoru nearly vomited. It felt like a demon had possessed his body.
Sarutobi Sasuke was a legendary figure, and now his chakra was merging with the young Uchiha's.
Next, Satoru felt dizzy—he sensed several other distinct streams of chakra entering his body as well.
"Good thing I didn't let the Nine-Tails' chakra in!" Barely after absorbing the chakra, he lost consciousness. When he came to, Satoru found the chakra in his body in complete chaos.
There was nothing to do but gradually return these strange chakra streams to their places in his body. He directed all the excess chakra into the Yin Seal.
Even so, the Yin Seal was overflowing. Only after repeated purification and concentration did he finally fully organize the chakra that had entered his body.
From then on, a diamond-shaped mark appeared on Satoru's forehead, just like Tsunade's.
Checking his chakra, he found he'd reached the peak Kage level! Just one step from breaking through to Super-Kage! And that didn't even count releasing the Yin Seal.
Satoru would grow, and his power would increase rapidly. Becoming the strongest shinobi in the world was only a matter of time.
"Is this the Previous Monkey King?" Satoru saw the staff on the ground and picked it up. The goal of his journey had been to save the Previous Monkey King. Now that the task was complete, he naturally needed to return to the Water Curtain Cave.
Satoru wasn't rushing to absorb the Nine-Tails' chakra or accept the Sage's heritage yet. He was developing fast enough already. Now he just needed to accumulate experience and keep getting stronger.
Besides, Satoru hadn't completed the task of awakening the Eternal Mangekyo Sharingan. Every use of the Mangekyo was a huge strain on his body.
His previous battle with the Nine-Tails Demon Monkey King had nearly cost him his life.
"Let's go, I'll come back next time," Satoru looked at the scattered red chakra around, licked his lips, and using the Diamond Staff in his hand, quickly reached the well's mouth.
Climbing out, he found the Monkey King waiting there.
"Ah! Satoru! You're finally back!" Enma was very excited.
"How much time has passed?" the young man asked.
"About two hours!" the Monkey King replied.
"What?!" Only then did Satoru realize that time flowed differently at the bottom of the well than above.
"Is that the staff, right?" He waved the Diamond Staff in his hand.