Late night. The special care ward of Konoha Hospital.
Moonlight streamed through the window, casting cold and clear patches of light on the floor.
On the hospital bed, Sasuke's eyes snapped open.
"Awesome!" He couldn't help but growl, his voice hoarse yet filled with extreme satisfaction.
Although his consciousness had been 'pushed' aside at the time, unable to control his body, the shared sensation had been extremely clear.
He could 'feel' the impact of his fist hitting Itachi's face, could 'hear' the sound of bones dislocating, could 'see' the shock, pain, and disbelief on that usually cold and proud face of Itachi.
'That feeling of every punch landing, beating Uchiha Itachi beyond recognition, was simply so satisfying!'
'Hahaha!' Sasuke laughed wildly in his heart. Although his body ached, his spirit was in a state of extreme excitement and pleasure.
At that moment, a calm voice sounded in the ward, interrupting Sasuke's thoughts.
'If it weren't for your inner desire to seek revenge yourself, I could have actually directly controlled your body during the day and killed him.'
"Great Senior! Is that you?" Sasuke shouted excitedly, ignoring the pain and trying to sit up.
"It's me."
"Thank you! Thank you for teaching that bastard a lesson for me!" Sasuke looked around the room. "Great Senior, where are you? Why can't I see you?"
"If I appear... don't be scared." The voice carried a hint of amusement.
"Scared? How could I be scared of my own savior?" Sasuke shook his head.
As his words fell, the air in the shadow of the wall opposite his bed slightly distorted.
A semi-transparent figure, emitting a faint golden-red glow, with an outline similar to a human but clearly without a physical body, slowly emerged.
The moonlight passed through his 'body', casting no shadow on the floor.
"Great Senior, you... have no shadow?" Sasuke asked instinctively, then a thought crossed his mind, and his voice carried a trembling hint of expectation.
"Could it be that Great Senior is a ghost? Can people really exist in this form after death?"
"Ghost? Something like that." Setsuna's spiritual body nodded, his tone calm.
"Then... then..." Sasuke's breathing suddenly quickened. "Great Senior, could I also see my mother and father? They... they also..."
Setsuna spoke slowly: "If you just want to see them, there is a technique called Edo Tensei that can help you."
"Edo Tensei?" Sasuke silently committed the name of this technique to memory.
The next moment, Sasuke, enduring the sharp pain all over his body, struggled and rolled off the hospital bed.
The sudden movement aggravated his wounds. He grunted, and cold sweat instantly seeped from his forehead.
But he didn't care. His knees went weak, and he knelt on the ground, heavily kowtowing to Setsuna with a loud thud: "Great Senior! Please accept me as your disciple!"
Setsuna's tone was calm: "The time I stay in this world is limited. If I train you, the methods might be almost cruel."
"I won't do anything step by step. I won't consider your endurance limits. I will only squeeze out every bit of your potential, even directly consume your vitality in exchange for short-term leaps in strength."
"Even so, are you still willing?"
Sasuke lifted his head sharply, no fear in his eyes, only an almost obsessive determination: "If I train like that, can I kill Uchiha Itachi?"
"Easily." Setsuna's words were concise.
"Then I am willing!" Sasuke almost roared it out. "As long as I can kill that man! No matter what the cost! No matter what pain I endure! I am willing!"
"Very good." Setsuna nodded slightly. "I do indeed intend to nurture a disciple in this world, to help me with one thing in the future."
"However, actually, the person I initially considered... was Uzumaki Naruto. His physical talent far exceeds yours."
Sasuke was initially a bit unconvinced, but thinking of Naruto's terrifying Chakra Reserves, he had nothing to say.
"But," Setsuna's voice pulled him back to reality. "The reason I changed my mind and chose you is because Naruto, at this stage, lacks one crucial thing compared to you."
"What is it?" Sasuke asked instinctively.
"The conviction to become strong!" Setsuna said calmly. "Naruto has his Ninja Way, but that's more of a conviction for 'protection' and 'proving himself'."
"Your conviction is 'revenge'. This kind of obsession often erupts into even more terrifying power in the initial stages."
Sasuke nodded heavily, the flame in his eyes burning even fiercer: "As long as I can kill Uchiha Itachi! No matter the cost, no matter what I become, I am willing!"
"Remember your words today." Setsuna said. "Then, as the beginning of our master-disciple relationship, your first test is here."
"Test?" Sasuke was stunned, 'I was now seriously injured in bed, what test could there be?'
Setsuna shook his head slightly: "Do you think the Konoha's higher-ups will have no reaction to the power you unleashed during the day?"
Sasuke's heart tightened, 'That's right, the events of the day had caused such a commotion. How could Konoha possibly ignore it?'
"I can teach you a technique to temporarily deal with the immediate difficulty." Setsuna said in a low voice. "This technique is extremely powerful and can turn the tide of battle at critical moments."
"But at the same time, it is extremely dangerous, especially for someone like you, deeply mired in hatred and obsession. You are more likely to be corroded by the 'demonic nature' inherent in this technique itself, ultimately dragging you into an abyss deeper than Hell."
"Can this technique help me get revenge?" Sasuke only cared about this.
"Of course." Setsuna affirmed.
"Please teach me, Master!" Sasuke did not hesitate, kowtowing again.
"Good. Focus your mind, feel this power..." Setsuna directly used Genrou Maou Ken on Sasuke.
Consciousness sank. Boundless darkness.
Sasuke felt as if he had fallen into a bottomless abyss, filled with terrible demons everywhere. The strength of each demon was terrifying to the extreme.
In this spiritual abyss, he began to run and fight.
No Chakra, no Ninjutsu, only the most pure contest of willpower and spiritual resilience.
He was repeatedly knocked down and torn apart by demons, feeling the pain of his soul being torn apart.
And time and again, relying on that obsession that refused to yield, that craved revenge and power, he struggled to stand up, continuing to climb and fight.
The sense of time here was completely chaotic. It could have been an instant, or ten thousand years.
Finally, after experiencing seemingly endless torment and fighting, he arrived at the summit of this dark abyss.
But when he looked up, he found the sky above was not the heavens.
It was a face so massive it was indescribable, as if it covered the entire universe.
The outline of that face was unmistakably his master.
But this face was aloof, majestic, like a god looking down upon motes of dust.
Its eyes were the sun and moon. The great sun sent down heavenly fire, burning him fiercely.
Those flames did not scorch his flesh, but directly ignited his soul.
Indescribable pain! A pain billions of times more intense than being torn apart by demons in the abyss!
Sasuke's eyes snapped open, gasping for breath, his entire body soaked in cold sweat.
He was still in the ward. The moonlight was cold and clear. His body still ached.
But in that illusion, he seemed to have spent endless time, far, far more powerful than Tsukuyomi's illusion.
Sasuke was shaken inwardly: 'Was that the actual feeling of the 'technique' Master just taught? Too terrifying! Just how powerful is Master's soul!'
If before this, Sasuke's understanding of this mysterious master was still at the level of vague awe, like a 'distant, unreachable yet radiant moon'...
Then, after personally experiencing the power of Genrou Maou Ken, he couldn't help but marvel that his master's soul was as vast as the Milky Way, as mysterious as the universe.
Shock, fear, and an indescribable desire for deeper power frantically bred in his heart.