At this moment, Naruto's eyes were still blue. He looked down at his body, feeling the will of hatred frantically eroding him, and shook the four tails behind him.
The tails swayed obediently according to his will. The second one on the left swung to the left, the first one on the right flicked upward—the four tails coordinated even better than his own fingers.
Under Absolute Control, Naruto had originally thought that mastering Four-Tails Form would take some effort, but he suppressed Nine-Tails's encroaching will with almost no exertion.
Four-Tails mode is strong, there is no doubt about that. Naruto could feel that his current strength, speed, and reaction time had all been elevated to a level far exceeding that of an Elite Jonin.
But for him, this mode was not good enough. The Four-Tails mode requires consuming a large amount of Nine-Tails Chakra to maintain the physical existence of the tails, and the tails themselves do not add much actual combat power. Frankly speaking, it is a berserk form with low Chakra utilization efficiency.
What Naruto really wanted was the Nine-Tails Chakra Mode or the Kurama Mode.
In this form, the Chakra cloak would change from dark red to a dazzling gold, without the materialized tails dragging behind consuming energy. It provides highly efficient energy utilization and extreme movement capabilities.
This is the true complete form of the Nine-Tails Jinchuriki, an advanced application that Minato spent years in the Shinigami's stomach to master.
If he could go one step further and stack Mount Myōboku's Sage Mode with KCM, that would be even more perfect.
However, Naruto knew that these things could not be rushed. The Four-Tails form was already quite good as an intermediate transition state, and he still had plenty of time to slowly research and develop it.
If he were to rush into the Sealing Space now and say to Nine-Tails, "Come on, Kurama, let's try to see if you can unlock Nine-Tails Chakra Mode for me!", he estimated that given Nine-Tails's current state, it would most likely refuse to cooperate.
With this in mind, he withdrew the Nine-Tails Chakra. The dark red Chakra cloak began to fade, and the four tails dissipated into red light particles in the air one by one.
Within a few seconds, Naruto had returned to his original appearance, standing in place without even a single tear in his clothes.
Inside the Sealing Space, Nine-Tails lay in the cage, watching Naruto enter and exit the Four-Tails mode as if it were nothing. The expression on its face was extremely complex.
It could see that this brat no longer needed to expend any effort at all to control its Chakra.
Would Naruto still need its cooperation in the future?
Would he just bypass it and drain all of its Chakra?
If that were the case, would it ever have a chance to break through the seal and get out in this lifetime?
While Nine-Tails was lost in these wild thoughts, Naruto's consciousness reappeared in the sewer. He stood in front of the cage and smiled at Nine-Tails.
"Thanks, Kurama."
Nine-Tails was stunned for a moment, its ears twitching involuntarily.
It thought it had misheard, this brat had just said "thank you" to it?
"Thank me?"
Nine-Tails narrowed its eyes, its tone filled with vigilance and suspicion. "Thank me for what?"
"Thank you for cooperating with me."
Naruto stuffed his hands into his pockets. He was indeed thanking Nine-Tails. Regardless of the purpose for which Nine-Tails agreed to cooperate with the experiment, the information value this round of experiments brought him was immense.
Nine-Tails was silent for a moment, then refocused its attention on the question it hadn't received an answer to.
"You still haven't answered me, why do you know my name? Also, what did you do to me just now? Why can you control my Chakra so easily?"
Naruto tilted his head, revealing a smile with a hint of mystery. "Kurama, you have a few too many questions. Maybe next time."
"Hmph!"
Hearing Naruto's words, Nine-Tails's ears pricked up, and a puff of air sprayed from its nostrils.
Seeing Nine-Tails's appearance, Naruto added a sentence, "I'll tell you next time I have a chance."
Nine-Tails turned its head to the side, and no longer looked at Naruto.
"Pretentious brat."
Nine-Tails rested its chin on its front paws, closed its eyes, and assumed a posture of "I don't want to deal with you anymore."
Naruto didn't mind. He stood where he was without leaving, starting to look up, down, left, and right at this Sealing Space.
His gaze swept over the damp dome above, the mottled walls on both sides, the shallow water under his feet, and finally landed on the giant cage covered in sealing talismans.
Oppressive.
This was his only assessment of this space.
It must be one of the reasons for Nine-Tails's continuous mania.
Although Nine-Tails had turned its head away to ignore Naruto, its ears remained pricked, capturing every subtle sound Naruto made.
It heard Naruto's footsteps and finally couldn't help but turn its head back a little, looking at Naruto with squinted eyes.
"Brat, what are you doing?"
Naruto turned to face Nine-Tails, and flexed his wrists. "Seeing that the space you are staying in is a bit oppressive, I'm giving you a change of environment."
Before Nine-Tails had time to ask "what do you mean by changing the environment," Naruto snapped his fingers.
Snap!
In an instant, the sewer's dome, walls, water, and rust all disappeared, replaced by an endless expanse of golden light.
It was the exact same structure as the golden space where Kushina was.
Nine-Tails was stunned and its slit pupils narrowed slightly.
Nine-Tails soon resumed its usual arrogant expression, and rested its chin back on its front paws. "Tch."
Naruto looked at Nine-Tails's expression, already understanding most of its thoughts in his heart.
Clearly liking it, but refusing to admit it.
Another tsundere.