Naruto: Copy System#727+728: I'll Trouble You to Teach Me, Persuading Big Sis Retsu to Study Medicine

"Bankai: Minazuki."

At last, Unohana Retsu unleashed her Bankai. Her blade transformed, becoming a wickedly curved katana.

The very space behind her seemed to bleed, weeping crimson tears, while her sword dripped with fresh blood.

Just the sight of her was pure terror. Most would have been frozen in fear, unable to even think of moving.

But Shin was no stranger to a grim spectacle. He had seen far worse. This was hardly enough to intimidate him.

'Her spiritual pressure skyrocketed, dozens of times stronger than before.'

Shin gauged her aura. After activating her Bankai, her Reiatsu had spiked by several dozen times.

Of course, a massive spike in spiritual pressure didn't translate to an equal multiplier in combat strength, but her overall power had still increased severalfold.

CLANG—!!!

Their swords clashed once more. This time, however, a chip appeared on the blade of the Shodai Kitetsu.

Shin’s brow furrowed slightly. He hadn't been using Armament Haki. He quickly coated the Shodai Kitetsu in a layer of black Haki.

When their blades met again, the Shodai Kitetsu remained unscathed.

Unohana watched him, her mind racing. She had no idea what kind of ability he was using. It was a power completely different from spiritual pressure.

"Impressive. Your Bankai has boosted your strength considerably... but it's still not enough."

Shin blocked one of Unohana's strikes, then countered with a slash of his own, sending her flying.

"It's been so long since I've felt the thrill of death's door... How exhilarating."

A smile spread across Unohana's face. Against the blood-red backdrop created by her Zanpakutō, that smile was utterly chilling.

"It's time to end this."

Shin sheathed his sword, then drew it again in a single, lightning-fast motion. A classic iaijutsu slash. The attack sent Unohana crashing to the ground.

She now lay weakly on the icy surface, her breathing shallow.

"Are you closing your eyes, waiting for death?" Shin asked, looking down at her.

After a long moment, when no final blow came, Unohana opened her eyes, a flicker of confusion in them.

"You're not going to kill me??"

"Not right now. You're more valuable to me alive than dead," Shin replied, shaking his head.

Unohana was one of the most powerful Soul Reapers. Shin needed her to teach him how to use spiritual pressure. He even planned to infiltrate the Seireitei, and for that, he needed her help.

A living Unohana was far more valuable than a dead one. Besides, they had no real grudge against each other. Why kill her?

"I don't know if this will work on you."

Shin used the Mystical Palm Technique. He had no idea if medical Ninjutsu would work on a Soul Reaper, but it was worth a shot.

Unohana felt a warm energy wash over her body, and her wounds began to close. The technique worked.

"Is that Kaidō (Healing Kidō)?"

Shin shook his head. He was using Ninjutsu, not some healing Kido.

Kidō was an advanced form of spellcraft used by Soul Reapers, divided into three categories: Hadō for offense, Bakudō for binding and defense, and Kaidō for healing.

"You're human, aren't you?? What is your purpose in the Soul Society?" Unohana asked him.

"Whatever your purpose, you should leave. This is not a place for you. You may have defeated me, but there are at least ten others in the Soul Society stronger than I am."

Before Shin could answer, Unohana warned him. She wasn't wrong. There were more than a few people in Soul Society stronger than her.

There was the Head-Captain, Genryūsai Shigekuni Yamamoto, and the leader of the Royal Guard, Ichibē Hyōsube, the monk who names all things.

The five members of the Royal Guard possessed combat power equal to the entire Gotei 13. Of course, at this point in time, the Royal Guard probably didn't have all five members yet.

Kirio Hikifune, for one, almost certainly hadn't joined.

Unohana was trying to persuade Shin to leave because he had spared her life. She refused to be indebted to anyone.

"Do you have a way to make it so others can't tell I'm human?" Shin asked with a smile.

After his fight with Unohana, Shin had a rough idea of where his strength stood in the world of Bleach. He was confident he could take on Yamamoto and not lose. Even if he had to face the Royal Guard as well, he wouldn't necessarily be defeated.

But he still planned on infiltrating the Seireitei. He wanted to learn the ways of the Soul Reapers.

Unohana's brow furrowed, and she shook her head.

"I can separate your soul from your body, but I can't hide your human identity."

"I see." Shin wasn't surprised. He hadn't really expected her to be able to.

"In that case, Unohana, I have a request. Teach me how to absorb spirit particles," Shin said.

"Why should I help you? We're not friends," Unohana said flatly.

"I did just spare your life. A little gratitude wouldn't be out of place, would it?"

Shin couldn't help but say.

"In that case, kill me." Unohana tossed her Zanpakutō towards him.

"You'd really just let me kill you? Aren't you going to get stronger and challenge me again someday? It's better to stay alive."

"How about this? You teach me about spiritual pressure, and I'll teach you swordsmanship?"

As he said it, Shin felt his face flush. He didn't really have anything to teach Unohana about swordsmanship.

When it came to pure technique, Unohana was far more skilled than he was. The only reason he had been able to dominate her was because he was overwhelmingly stronger.

"You'll be my sparring partner in the future. Then I can teach you."

Unohana stared at him for a long time before finally making her offer.

"That's no problem at all." Shin smiled. It was a win-win situation for him. Why would he refuse?

Afterward, Shin brought Unohana out of the Amenominaka dimension.

"By the way, why did you come here? Was my arrival really that loud?" Shin asked her.

"Your arrival in the Soul Society certainly wasn't quiet. But the other Soul Reapers probably didn't notice. This place is far from the Seireitei."

Unohana had been in the eastern Rukongai, which was why she had noticed the disturbance and come to investigate. It was unlikely anyone else would have.

"That's good. I was worried others would discover my tracks. That would have been a headache."

Shin breathed a sigh of relief. He had just arrived in the world of Bleach and didn't want to become a public enemy of the Soul Reapers just yet.

If Yamamoto found him, it would be a real hassle...

His plan to infiltrate the Seireitei would have to wait until he could properly conceal his identity. He needed a way to make others see him as a Soul Reaper, not a human.

<><><><><><><><>

Under Unohana's guidance, Shin began to voraciously absorb everything she could teach him about Soul Reapers, while also attempting to gather and absorb spirit particles to condense into spiritual pressure.

"You can actually absorb them?" Unohana was surprised when he succeeded.

But she didn't know much about humans. After a moment of surprise, she reasoned that perhaps some humans possessed such abilities. Just like the Quincy, who could also manipulate the spirit particles in the atmosphere to form weapons.

But Shin's method of absorption was different from the Quincy's. If she didn't know for a fact that he was human, she would have mistaken him for a Soul Reaper.

"You've been out for so long without returning to the Seireitei. Will you be alright?"

A week had passed. In that time, Shin had made considerable progress. He could absorb spirit particles and already had a vast amount of spiritual pressure within him. This was even after deliberately restraining his absorption and considering the scarcity of spirit particles in the area.

He was holding back to avoid causing a commotion and attracting the attention of other Soul Reapers. He didn't want to be so high-profile.

"I'm the captain of the 11th Division. I'm usually fine," Unohana replied.

By now, she and Shin had become quite familiar. Though she knew he was an intruder, she showed no hostility towards him. At most, she would challenge him to a duel. The Unohana of this era was a true battle maniac.

The reason she was in the Rukongai was because there were no battles to be had. Her hands were itching for a fight, and she was considering killing a few souls in the Rukongai for sport.

Yes, that's right. Unohana was a true villain. She was known as the greatest criminal in Soul Society's history. It was only after being defeated by Yamamoto that she joined the Gotei 13.

Shin nodded at her words, then used the Multi-Shadow Clone Jutsu.

He was currently using his spiritual pressure to research a technique that could hide his true nature, a technique that would prevent other Soul Reapers from seeing him as human. This was something he had to research on his own.

He had been at it for several days and had some leads, especially with the help of several thousand shadow clones. When it came to training, the Shadow Clone Jutsu was the ultimate cheat code for training. Several thousand shadow clones were like several thousand people researching together, and their progress could be shared.

In the blink of an eye, about half a month had passed since he arrived in this world. Shin returned to the System Space to check on Kushina and the others. He had also managed to completely placate them. It wasn't easy for him, either.

Afterward, Shin had successfully developed a way to hide his identity. Even Unohana, if she didn't already know, would never have guessed he was human.

"It seems you've succeeded." Unohana's expression was complicated.

"Aren't you going to kill me? I'm the only one who knows your identity. If you kill me, you can infiltrate the Soul Society completely. No one will ever find out."

Unohana's expression became even more complicated as she spoke, wondering what he would choose.

"Do you think I'm that kind of heartless person?" Shin asked, speechless.

"Then you're not worried I'll leak your identity?" Unohana glanced at him.

"Not at all. I trust you won't."

Shin smiled faintly, completely confident that Unohana wouldn't betray him. If she had wanted to, she could have done so long ago. The Bakudō spell, Tenteikūra, could be used to transmit messages to other Soul Reapers. If she wanted to expose him, she would have done so already. So, Shin trusted her.

"Then thank you for your trust." Unohana smiled.

This was the first time Shin had seen her smile since they met. After all, the Unohana of this era was extremely cold.

"It's been a while since you've smiled. Your smile is a little... stiff," Shin commented.

Unohana's smile vanished, and her expression darkened.

"Shin, don't you know how rude that is to a woman?"

Unohana was not happy. Her hand was even on the hilt of her sword, as if she were about to fight him.

"Sorry, I've never thought of you as a woman." Shin shrugged. The current Unohana was practically a female Asura.

"Is that so."

Unohana lowered her head, as if in thought.

"Could I trouble you for a favor, Unohana?"

Hearing Shin's words, the intelligent Unohana immediately guessed his intentions.

"You want me to take you to the Seireitei, don't you?" she asked.

"Smart. You guessed it right away. We haven't known each other for long, but Big Sis Retsu seems to know me well," Shin said with a smile.

Unohana glanced at him. What kind of address was "Big Sis Retsu"? But it wasn't wrong for him to call her that. He wouldn't be losing out by calling her "sis."

In terms of age, Unohana was much older than Shin. Even if you added up his age from the Naruto and One Piece worlds, plus his age before transmigration, it still couldn't compare to Unohana's.

The lifespan of Soul Reapers was long. Though Shin hadn't asked, he guessed Unohana had lived for at least a few hundred years.

"So, will you help me?" Shin asked.

If Unohana helped him, he could get a legitimate identity. If not, he had other ways to get in.

"Alright, I'll help you." Unohana nodded. This was probably the first time she had helped someone.

But now, she and Shin could be considered friends. She didn't have many friends. The cold and distant her had none at all. Shin was probably her only friend now. Others would run away at the mere mention of her name.

"Big Sis Retsu, have you ever thought about studying medicine?"

Shin suddenly asked, making Unohana stop and look at him with confusion.

"I just feel that your Zanpakutō's Shikai is very suitable for saving people."

He knew he was playing with fire, trying to push the greatest killer toward a path of healing, but Unohana's Shikai was indeed the strongest healing-type Zanpakutō.

Unfortunately, the current Unohana only knew how to kill. She had no idea how to save people, and she hadn't even started learning Kaidō. The reason Unohana started learning Kaidō in the first place was to engage in even more thrilling battles.

"Perhaps I can consider it." Unohana glanced at Shin and nodded thoughtfully.

"Shin, I have a question for you." Unohana's expression turned serious.

"Go ahead. As long as it's not too difficult, I'll answer," Shin nodded, wondering what she wanted to ask.

If it involved any of his secrets, Shin definitely wouldn't answer. After all, some things really couldn't be said.