Rei stained his Asauchi with blood to show his resolve: he would achieve Bankai even if it killed him. Blood Drink finally saw his resolve and only then became willing to undergo Bankai.
Without the resolve to die, Rei could not achieve Bankai in his current state. That was right—even though his base Reiatsu had already reached Captain-level, he still could not achieve Bankai easily.
In the original timeline, many people's Bankai had limitations: some lacked sufficient Reiatsu, some placed a tremendous burden on their bodies, and others were so powerful that they could easily hurt nearby friends.
The fact that Rei's conditions for Bankai were so harsh meant that it was extraordinary. Its abilities were definitely no slouch...
"What? Are you that impatient? Taking some time to grow before attempting Bankai is the perfect approach."
"No need. Let's go somewhere else and start!"
Blood Drink had reappeared with a smile on his face. His attempt to dissuade Rei had failed, and Rei insisted on beginning Bankai.
Rei took Blood Drink and raced toward the Outskirts as fast as he could. By the time they reached a place far from any settlements, the sky had long since gone dark...
The night wind blew in gusts, and dark clouds gathered overhead, blotting out the stars. The two stood facing each other in a mountain valley. Several Ragged Hollows in the surrounding bushes had been frightened away, leaving only Rei and Blood Drink.
Once a Zanpakuto had materialized to the degree required for Bankai, everyone could see it. It was no longer like before, when only Rei could see him and Kenpachi Zaraki, standing opposite him, could not.
"What? Aren't you going to explain the rules or something?"
Rei broke the silence and asked. He no longer had a weapon in his hand, and neither did the materialized Blood Drink opposite him.
"There are no rules. Just defeat me with everything you've got, even your life. Show me your resolve."
As soon as Blood Drink finished speaking, a sword appeared in each of their hands, and the battle with the Zanpakuto began...
In the quiet valley, sword energy surged in an instant, and terrifying Reiatsu spilled out in all directions. Birds and beasts on the mountains fled in fright.
This time, Blood Drink was unlike he had been in the inner world. There, he had merely shattered Rei's Asauchi and driven him out. Now, Blood Drink seemed intent on taking Rei's life, every strike aimed at a vital point.
Blood Drink had taught Rei many of his moves, and Rei had figured out few on his own. Blood-Coagulating Piercer was one of them, but Blood Drink could use it now too, and when the two clashed with it, they were evenly matched.
The materialized Blood Drink's Reiatsu was on par with Rei's own, but his moves were more ferocious. The bloodsucking ability was disabled, and every time their swords clashed, they traded wounds that could not heal.
At a time like this, it came down to willpower, to see who could endure more. But at this point, that no longer mattered... Since Blood Drink had been willing to materialize, that meant Rei was bound to achieve Bankai. Surely Bankai couldn't kill its own master...
When Rei had not returned late that night, Maki sent a group of vassals to look for him. At around four in the morning, they finally followed his Reiatsu and found him lying in a pool of blood.
Rei looked as though he had only one breath left. The earth in the valley had been churned up layer after layer, and several enormous slash marks scored the surrounding mountains... The guards who arrived first concluded that a great battle had taken place here; the terrain had been devastated beyond recognition.
"Lord Tsunayashiro, are you all right?"
Kuzō, the captain of the guards, rushed over anxiously. He had been the first to find Rei.
"I'm fine. Make a stretcher and carry me back. I don't want to move!"
Rei's exhaustion could not conceal the smile on his face. Seeing that their master was happy, the guards who arrived afterward finally relaxed.
Kuzō had once been a gang boss in Kugawa Castle. His organization had been on the same level as the Eight Dragons Group, which Rei had wiped out.
After seeing a fellow gang wiped out, the man had come to challenge Rei out of admiration for his strength. Defeated in single combat, he had disbanded his organization and become one of Rei's followers.
North District 10 of Rukongai was vast, and quite a few formidable figures had risen to prominence there, but the Nangong Family remained the most famous. Not only were its various businesses thriving, but its head was also very strong.
"Who could have wounded you like this, big brother..."
"No one else. I did it while training. Don't worry about it."
Maki had come too. He had thought Rei had encountered one of the captains and been badly injured, but when Rei denied it, Maki asked no more.
It was mainly the sword and blade marks at the scene that had unsettled Maki. Aside from a great battle between Big Brother Rei and someone at captain or vice-captain level, he could not think of anyone capable of such destruction...
Rei had learned how to achieve Bankai. He had not let go of his sword even when he collapsed, and Blood Drink had fully acknowledged him. But Blood Drink had warned him not to use the technique yet, because it would place a tremendous burden on his body.
Only when his body and Reiatsu had fully matured to their peak would he be able to use it without too many problems.
So, to wield the power of Bankai, Rei ate voraciously, slept heavily, and trained relentlessly at home every day, improving his basic abilities.
The Tenshintai had not yet been invented. Even formidable geniuses needed at least ten years to progress from Shikai to Bankai, but Rei had taken only three years to go from forming his Zanpakuto to achieving Bankai. His speed was already far beyond those geniuses'.
Yanis brought up the plan to train in Hueco Mundo again, but Rei felt it would be safer to wait until he could use Bankai proficiently, so he pushed it back.
A year passed in the blink of an eye. Two hundred and sixty-six years before Aizen was sealed, the Nangong Family expanded its grounds, adding an enormous Training Ground. No one could stop them or come looking for trouble.
That was how things were in Rukongai. As long as you had ability and a little wealth to start with, you could easily establish your own domain without spending much time managing it yourself.
After all, so many people came seeking to attach themselves to you. All you had to do was screen them a little and put them in the right positions...
"Hyah!!!"
Clang! Clang! Clang!
Shouts and the clashing of weapons rang out constantly across the spacious Training Ground. Dozens of people sat cross-legged while three fought back and forth in the center.
Kuzō and Maki joined forces against Rei. They took a terrible beating, but every time they fell, they struggled to their feet with all their might.
Against a Captain-level opponent, the two would have been defeated in an instant if Rei had not held back. This amounted to Rei giving them free instruction. After defeating them, Rei stood still, and that was the end of the day's session.
Having completed a day of dull, tedious training, Rei went for a stroll through the streets of Kugawa Castle, accompanied by several guards.
When he reached the Hot Pot Restaurant his family owned, Rei walked straight in. The restaurant was nicely furnished, and since it was mealtime, many people were eating there.
As soon as Rei stepped inside, his powerful Reiatsu drew the attention of everyone in the restaurant. Most of the customers had Reiryoku, and quite a few Soul Reapers had come because of his reputation.
"Who is that? What terrifying Reiatsu!"
"A long red robe and short-to-medium hair covering his eyes. That's the head of the Nangong Family."
"Amazing..."
The whispers downstairs prompted a pair of men in a private room on the second floor to chat. Both could sense just how much influence the Nangong Family had in this district.
If Rei had been there, he would have recognized them. One was the flamboyantly dressed Shunsui Kyōraku, and the other was Kuruyashiki Kenpachi, whom he knew well...
"That young man's really impressive! That's Captain-level strength, isn't it?"
Shunsui Kyōraku sounded amazed, but his eyes were perfectly calm, showing little reaction.
"Of course. You two haven't met yet, have you? I'll have him come up and meet you."
Smiling, Kuruyashiki released a little Reiatsu to draw Rei upstairs. Kyōraku also happened to want to see what the much-discussed genius of Rukongai was like.
Downstairs, Rei had just been about to sit down to eat when he sensed Kuruyashiki's Reiatsu. He used Shunpo to move into a small private room on the second floor.
Rei's sudden disappearance startled the guards briefly, until his voice came from upstairs. "Captain Kuruyashiki, you actually have time to come here for a drink? Are captains all this idle?"
Rei glanced over and saw Shunsui Kyōraku sitting opposite Kuruyashiki. His outfit surprised Rei a little. Shunsui Kyōraku was one of the few Soul Reaper Captains he remembered.
The six episodes of Bleach he had watched included Shunsui Kyōraku's fight with the No. 1 Espada. The man was powerful; he had ambushed and killed the First Espada without even using Bankai.
"Captains are people too. We have everyday lives, you know! Speaking of which, I'm surprised you've learned Shunpo, young Nangong!"
Kuruyashiki looked surprised, but his acting was so poor that Rei knew he was pretending.
"And this is..."
Rei looked at Shunsui Kyōraku, whose flamboyant pink robe covered his Captain's Haori, and decided to pretend he did not know him.
"I'm Shunsui Kyōraku, the humble captain of the Eighth Division. A pleasure to meet you, young Nangong!"
Kyōraku also appeared easygoing, but inwardly he had already concluded that Rei was someone capable of threatening Seireitei's safety. He intended to test Rei's strength now and gather more information.
"I wouldn't presume to instruct you. I'll have to rely on the two of you captains for guidance..."
Rei wore a modest smile. Kuruyashiki and Shunsui Kyōraku then invited him to sit down and drink. Rei could hardly refuse their kindness, so he sat down at once and drank with the two old hands.
After several years in this world, he had long since gone from a boy of fifteen or sixteen to an adult. Drinking was no concern at all; the important thing was getting to know these two Captain-level figures.
Shunsui Kyōraku was the captain of an intelligence division and was very easygoing in conversation, but through their chat he learned about Rei's family background and all sorts of other information.
"That kind of power in three years. Beating Yama-jii is just around the corner..."
As the drinks flowed, Kyōraku brought up the dream Rei had once mentioned, a broad smile on his face. Kuruyashiki had of course told him about it.
"Speaking of which, I have Captain Kuruyashiki's guidance to thank. Otherwise, I wouldn't have even gotten close to Bankai. Thank you very much..."
Buoyed by the alcohol, Rei got straight to his feet and bowed to Kuruyashiki in thanks. The shaggy-haired man had not only saved him, but had also inadvertently enabled his Zanpakuto to materialize.
"You can already use Bankai, young man?"
Kyōraku was genuinely surprised this time. Rei was too much of a genius, practically a monster.
"Not yet. Only materialization, but I'm close!"
In response to Kyōraku's question, Rei told a small lie.
A genius. If he keeps growing at this rate and still doesn't join Seireitei, Yama-jii may not be able to hold back!
Kyōraku and Kuruyashiki exchanged a glance, both thinking the same thing. The Gotei 13 represented justice, but there were also some dark things within it...
The three drank until their faces were slightly flushed. Somehow, Kuruyashiki suddenly said he wanted to spar with Rei, and Rei agreed.
Both sides had their own hidden intentions. Rei wanted to gauge the strength of Captain-level fighters, so he could prepare to challenge them and join their ranks later. Kyōraku and Kuruyashiki, meanwhile, wanted to gauge Rei's current strength and judge how dangerous he was...