Unexpected Delight  

Ailin abandoned the use of his other abilities and instead focused on honing the single sword strike, following the path laid out by his "past self." It was a promise he had made, to refine this technique into his ultimate weapon.

Closing his eyes, Ailin relaxed his body. In a single moment, his entire being unified, strength flowing from the soles of his feet, through his body, and converging into his right hand. Then, with a flash of white light, his blade emerged from its sheath.

Shhh!

Under a large tree at the edge of the training grounds, Tsukishima looked up abruptly, staring in shock. The young man before him had already sheathed his blade, leaving behind a cleanly bisected wooden post as proof of his strike's power.

"How is this possible?" Tsukishima thought, bewildered. "Just a while ago, he needed my guidance to improve his technique. How did he master it so quickly?"

He hurriedly examined the "Book of the End" in his hand, a record of Ailin's life spanning over a century. To gain a deeper understanding of Ailin, Tsukishima had reviewed his life countless times after inserting his consciousness into the book. He had meticulously planned every step, marking the pages with notes on when to reveal his presence, where to gain Ailin's trust, and when to secure his unwavering loyalty.

But now, Tsukishima discovered that the records of Ailin's life trajectory in the "Book of the End" had faded, leaving only the past four years since their initial encounter.

"Flutter, flutter, flutter..." Tsukishima flipped through the pages, but no matter how many times he tried, everything after the entry "After four years of dedicated training, Ailin finally created his own ultimate technique – The Cut!" was blank.

This was the first time Tsukishima had encountered such a phenomenon.

Simultaneously, his memories of Ailin's life began to blur and eventually vanished completely.

Ailin, observing Tsukishima's frustration from under the tree, smiled faintly.

"Hmph, not everyone is worthy of witnessing my life," he thought. "Besides..."

In Tsukishima's "Book of the End," the protagonist was his "past self." Ailin had used the book to replace his "past self" with his own consciousness. However, he was also bound to fulfill the wishes of his "past self."

From that day forward, Ailin's performance at the Shin'ō Academy took a dramatic turn. With his exceptional swordsmanship, he defeated opponent after opponent. His classmates, who once mocked him, now avoided him, fearing his potential resentment.

However, they soon realized their worries were unfounded. Ailin remained unchanged despite his achievements, his focus solely on training.

When it came time for the fifth-year students to receive their Asauchi, Ailin chose not to participate, continuing to practice with his wooden training sword. He intended to imbue this blade with his perfected strike over the next hundred years, transforming it into a "Noble Phantasm" – a shining example of his "past self's" efforts to protect his "present self."

...

Within the black, grid-like space of Yukio's game, Tsukishima opened his eyes, a flicker of fear momentarily crossing his gaze before giving way to confusion.

"Well? Tsukishima," Ginjo asked expectantly.

Having raised Tsukishima from a young age, Ginjo was well aware of his abilities. The power to insert his existence into the past of others allowed Tsukishima to uncover their deepest secrets, even those they themselves might not be aware of. It was a power that could fundamentally alter a person's being.

Upon learning that Tsukishima had successfully intervened in Ailin's life, Ginjo had instructed him to memorize Ailin's training methods and how he guided his three disciples...

This way, Ginjo could learn everything about Ailin through Tsukishima. As Ailin had said, after just half a month of his guidance, Ginjo had achieved Bankai within a few decades without encountering any bottlenecks.

While Ginjo had no doubt about his own talent, he also acknowledged that without Ailin's initial instruction, achieving his current level of strength would have taken far longer.

"I'm sorry, Ginjo," Tsukishima said, his voice laced with disappointment. He presented his "Book of the End" to Ginjo.

"Ginjo, the difference in reiatsu between me and that man was simply too vast, so much so that my ability was rendered useless against him."

"After I inserted my existence into his, I realized my power had failed. I couldn't see his life, nor could I find an opportunity to infiltrate it. In that man's life, I was probably just one of many insignificant supporters, someone he wouldn't even remember. And after leaving his life, all memories of it vanished from my mind."

Even Tsukishima couldn't help but feel a sense of bitterness as he spoke.

Fullbring was the power of "love." Tsukishima's ability to insert his existence into the lives of others stemmed from his deep-seated desire to be needed, a longing that originated from his abandonment by his parents. He yearned to be someone others relied on, to experience camaraderie and adventure with friends...

"Therefore, I apologize, Ginjo... I couldn't obtain any information from his life. However, I vaguely recall that he was constantly training in swordsmanship... It's highly likely that his greatest strength lies in his swordsmanship. If you encounter him again, Ginjo, remember to maintain your distance. Don't get too close to him."

Bam!

"Damn it!"

Ginjo punched the wall of Yukio's game space, causing it to pixelate.

"Be careful, Ginjo," Yukio warned, "If this space is destroyed and that man finds us again, we're all doomed."

With Ginjo's current reiatsu, the game space could barely contain him. It was only because Ginjo had suppressed his spiritual pressure that Yukio had managed to pull him into his game.

"Yeah, I understand, Yukio. I'll be careful," Ginjo reassured him, placing his hands in his pockets. Suddenly, he seemed to remember something and looked around.

"By the way, Yukio, where's my body? Where did you put it?"

Yukio's eyes widened in realization. "Oh no, Ginjo's body is still back at my mansion."

"Should we go back and check if that man is still there? We can retrieve Ginjo's body while we're at it," he suggested.

Tsukishima and Giriko remained silent. They had no desire to face Ailin again. However, if Ginjo wished it...

"Forget it," Ginjo shook his head, "I remember placing my body in front of Ailin. When I attacked him earlier, that entire area was caught in the blast."

"Even if we retrieve my body now, it's probably useless. Besides, in my current state, having a body or not doesn't make much difference... It's not worth the risk."

"Right," the others agreed, relieved that Ginjo had decided against returning for his body. Avoiding another encounter with Ailin was a blessing.

...

"What an unexpected delight," Ailin chuckled, standing amidst the ruins of Yukio's mansion.

After carefully examining himself and confirming that Tsukishima's reiatsu was no longer present, Ailin opened his eyes. He hadn't anticipated such a pleasant surprise during his trip to the World of the Living.

Rising from the debris, Ailin brushed the dust off his clothes, drew his Zanpakuto, and thrust it towards the space before him.

Rumble...

A white light flashed, and two wooden doors materialized in the air, swinging open to reveal the Senkaimon, the passage back to Soul Society.

Stepping through the gate, Ailin vanished from the World of the Living...

"Welcome back, Captain Ailin."

Upon his return to Soul Society, Ailin found himself in the courtyard of the 13th Division. To his surprise, Jushiro Ukitake was waiting for him, despite the late hour.

"Eh? Captain Ukitake, you're still awake?" Ailin asked, surprised.

Ukitake, having sacrificed his lungs to the "God of the One Eye" during a childhood illness, often remained in a weakened state. As the host of the God's power, he typically spent this time of night resting in bed.

"Hahaha..." Ukitake chuckled, "My health has improved slightly these past few days, so I no longer need to be bedridden as often as before."