Aizen: Want to See My Shikai?

"Oh? Captain Unohana comes to the academy to teach as well?"

Lu Li was somewhat surprised to hear that.

Hachigen Ushōda nodded. "Of course. Quite a few Captains in the Gotei 13 come teach for a period every year. And since the Fourth Division also needs to recruit Shinigami skilled in Healing Kidō, Captain Unohana often comes to teach as well. You could say she's screening future Fourth Division members."

He glanced at the students practicing Hadō in the open space and continued, "The classes I substitute for mainly teach Hadō, though I also share some insights on Bakudō. Healing Kidō, on the other hand, has been separated into its own Elective Course. It's usually taught by Seated Officers, vice-captains, or Captain Unohana from the Fourth Division."

Lu Li understood after hearing this. Healing Kidō was the most delicate of delicate arts, and there truly were not many Shinigami talented in it. Besides, most young people who entered the True Spirit Arts Academy had ambitions in their hearts. More of them preferred fighting and killing, and did not want to do support work.

Thus, recruiting for the Fourth Division had always been a problem. Healing Kidō was offered as a separate course, and those who chose it and attained proficiency would most likely join the Fourth Division in the future.

After class, Lu Li and Aizen returned to their dormitory after a satisfying meal in the Cafeteria.

"Sōsuke, if we want to take the academy's Elective Courses, do we need to apply in advance?"

Lu Li asked curiously. Although he had transferred in midway through the term, since the academy offered Elective Courses, they should at least have given him a timetable to choose from.

"Not really. The True Spirit Arts Academy has many Elective Courses, and you can simply attend them. But if you want a grade, you'll need to pass the Examiner's test during the final exams. Only then will it be entered into your records. When the divisions select new members in the future, they'll most likely choose them by looking through those records."

Aizen explained, "What is it? Does Lu-kun want to take Healing Kidō?"

Lu Li nodded. "I'm somewhat interested in Healing Kidō."

"So you can enjoy battle even more? Lu-kun, you really are belligerent."

Aizen felt that he was beginning to understand Lu Li. Like himself, Lu Li was a peerless genius, but he had no deep schemes. He was simply a straightforward, battle-loving brute.

Aizen did not dislike people like Lu Li. On the contrary, having a fellow genius as a roommate added quite a bit of interest to his boring life.

"Sōsuke, don't you think battle is interesting? I always feel that you'd make a very good opponent."

Lu Li asked with a smile. Aizen was currently hiding his strength, and on the surface, his Reiatsu was about the same as Lu Li's—both were Grade 17. According to Aizen himself, he had been Grade 19 when he first entered the academy, and his current Reiatsu was the result of diligent training.

In truth, Lu Li felt that Aizen's actual Reiatsu grade had to have the leading "1" removed, at the very least.

"You jest, Lu-kun. I'm no match for you. Whether in swordsmanship or Hakuda, I'm not your opponent, and your talent in Kido is better than mine as well."

Aizen said, then changed the subject. "By the way, I see that Lu-kun already has his own Asauchi. Although you haven't taken any classes on Zanpakuto yet, I can teach you some knowledge about Zanpakuto and Reiatsu improvement in advance."

"Oh?"

Lu Li perked up. "Then I'll have to ask Teacher Sōsuke to instruct me."

Aizen smiled. "Lu-kun, you should not call me that. I only know a little about these things myself. At most, I can help you prepare before the lessons."

Next, Aizen explained the basic knowledge of various Zanpakuto, as well as methods for cultivating Reiatsu.

Aizen's purpose was simple. He did not dislike Lu Li. Rather, he quite liked his genius roommate. There was no harm in building a good relationship, and if Lu Li became stronger, perhaps he would be useful to Aizen's future plans.

Moreover, Aizen now wanted to know whether Lu Li was an all-round genius like himself—whether he possessed talent in Zanpakuto resonance and Reiatsu as well.

Aizen truly was a good teacher. Lu Li found Aizen's explanations easier to understand than the theoretical lessons from the several teachers during the day.

First came the matter of raising Reiatsu. Since Shinigami were formed from high-density Spirit Particles, raising Reiatsu meant increasing the density of Spirit Particles within oneself.

This could be achieved through a nutritious diet, absorbing Spirit Particles from the outside world and compressing or refining them into one's spiritual body, as well as physical training and other methods.

Yes, exercising could also raise Reiatsu. The strength of a Shinigami's "body" was essentially an increase in soul density, so even conventional physical exercise was an effective method of raising Reiatsu.

However, Aizen did not usually use that method. He possessed extremely strong control over Spirit Particles, so he absorbed the free Spirit Particles floating in the air, gathered and absorbed them, and thereby increased the density of his spiritual body to raise his Reiatsu.

Aizen's theory roughly matched Lu Li's speculations from when he had read the manga. For instance, during the Thousand-Year Blood War arc, eating at Kirio Hikifune's place could raise Reiatsu. Her words had seemed to mean that eating food containing her Spirit Particles could increase Reiatsu.

Another species in this world—the Hollow—likewise devoured its own kind to obtain Reiatsu and evolve upward. Hollows could raise their Reiatsu by consuming other Hollows.

Taken together, it seemed that raising Reiatsu was fundamentally about increasing the binding strength between Spirit Particles.

That was why Aizen's Reiatsu was so powerful. On one hand, his talent gave him a naturally high Reiatsu limit. On the other, his "cultivation" speed was also very fast.

Besides the usual methods of cultivating Reiatsu, there was also a way to explosively raise it: Zanpakuto release.

One thing needed to be made clear here: not every Zanpakuto increased its wielder's Reiatsu after being released. Rather, most Zanpakuto did not have that function.

The feeling that one's Reiatsu had increased after Shikai or Bankai was merely an illusion. In essence, the releaser's Reiatsu had not increased; only their output had changed.

For example, if a Shinigami originally had a Reiatsu of 100 and their maximum single output before Shikai was 5, then after Shikai, their maximum single output would become 10. With Bankai, it could reach 40 to 50.

There were also a small number of Zanpakuto that truly could raise Reiatsu to a certain extent after release. For example, the Zanpakuto of that overpowered Ichigo Kurosaki showed an obvious increase in Reiatsu after Bankai. Then there was Kenpachi Zaraki's Zanpakuto—after his Bankai, even his opponents could clearly sense his Reiatsu rising.

However, Zanpakuto that could raise Reiatsu after release were ultimately rare, and the increase was usually not very great. Ichigo was an exceptional case because he was the protagonist.

Still, in general, a Shinigami who had mastered Zanpakuto release and one who had not were on completely different levels of combat power.

Therefore, if Lu Li wanted to significantly increase his strength, mastering Zanpakuto release would have the most obvious effect.

Yet there was a problem with that as well. Learning Shikai was not easy. First, one needed a certain baseline level of Reiatsu. Grade 17 Reiatsu only barely reached the threshold of Shikai.

Those who could usually learn Shikai were Seated Officers of the Gotei 13, and Seated Officers possessed at least Grade 10 Reiwei.

According to Aizen, the higher one's Reiwei grade, the easier it was to resonate with one's Zanpakuto. This represented a deeper degree of development of one's own soul power, while a Zanpakuto's Shikai was, in truth, a manifestation of a Shinigami's soul.

Put plainly, an Asauchi was merely an Asauchi. Only after one infused it with one's own soul did it become a true Zanpakuto.

And a Zanpakuto's abilities would be influenced by the Shinigami's soul. Taken to an extreme, it could be understood as something formed by a Shinigami's soul being projected outward.

"Sōsuke, you're the top student around here. Have you learned Shikai?"

Lu Li asked curiously, mainly wanting to see Aizen's reaction.

Yet to Lu Li's surprise, Aizen, who had always concealed his abilities, actually nodded this time. Smiling, he said, "My Zanpakuto is called Kyōka Suigetsu. It is a flowing-water-type Zanpakuto that can disturb enemies through the chaotic refraction of mist and water, causing them to kill one another."

He sat cross-legged on the bed, stroked Kyōka Suigetsu before his knees, then looked at Lu Li. "Lu-kun, would you like to see my Zanpakuto?"