Infinite Potential of the Shinigami

Yamada Seinosuke clearly understood his role as a tool. Every so often, he would bring new surprises. The last time, it was a Shinigami version of Cero using Kido; this time, it was progress in developing Inner Kaido. In this field, Yamada Seinosuke had unmatched talent.

Laboratory 13

The lab was entirely silver-white and built with the most durable materials. The floors, walls, and ceiling were inscribed with the Kido spell for Dankū, providing maximum defence. The inscriptions also helped conceal reiatsu, preventing chaos within the squad's barracks.

Under Tokikaze's surprised gaze, Yamada Seinosuke raised his Zanpakutō and struck his left arm hard. Blood spurted out spectacularly like a fountain.

"Do you have to go this far..."

Ignoring Tokikaze, Yamada Seinosuke gritted his teeth against the pain, spreading his right hand, which began to glow with a faint green light—the distinct hue of Kaido.

"Inner Kaido: Path One, Life Regeneration!"

Yamada Seinosuke's chant was clear to Tokikaze, who realised this technique resembled the naming convention of Ichibei Hyosube's Inner Hadō. Suddenly, Tokikaze saw Yamada Seinosuke in a new light—a true genius in Kaido for the past millennium in the Fourth Division.

As Yamada Seinosuke's chant concluded, the healing light transformed into vines that wrapped around his wounded arm. In mere moments, the bleeding stopped, and the gaping wound began to heal visibly. Tiny flesh buds sprouted and intertwined, continuously mending the gap. In an instant, everything was back to normal, save for the blood on his skin, which was the only evidence of the near-severed limb.

"Kanae's eye regeneration gave me great inspiration," Yamada Seinosuke explained. "Though it caused some mutations, the benefits outweigh the drawbacks. Now, Kanae's eyes can see through illusions, analyze reiatsu flow, and detect weaknesses—abilities that enhance with his reiatsu."

"Based on this, I discovered that Inner Kaido, or rather Inner Kido, draws from the power of the soul!" His face showed excitement and a hint of madness.

In a way, he resembled Mayuri Kurotsuchi.

"Using the soul's power to fuel Kaido can increase its effectiveness tenfold or even a hundredfold."

Yamada Seinosuke, engrossed in his explanation, didn't notice Tokikaze's somewhat odd look. "Mapping the reiatsu trajectory for Kaido requires extensive time to deduce."

Casting Kido wasn't just about chanting; it involved channelling reiatsu through specific pathways in the body to form the spell's structure.

Developing new Kido spells was no simple task, let alone Inner Kaido.

That Yamada Seinosuke had made such progress in a short time was impressive.

However, given his exceptional Kaido talent, extensive expertise in human anatomy, the Adjuchas infused with the Spirit King's power, and Kanae's willingness to sacrifice for science, it made sense.

"Mayuri Kurotsuchi also significantly contributed to the development of Inner Kaido," Yamada Seinosuke acknowledged, his excitement dimming slightly. "As detestable as he is, his scientific prowess is undeniable."

"Additionally, there's someone else you should be aware of, Captain Tokikaze."

"Who is that?"

"My dear brother, Hanatarō Yamada."

Yamada Seinosuke spread his hands helplessly. "Although he is incompetent and cowardly, he has some talent in Kaido. Life Regeneration partially owes its development to him."

The mention of Hanatarō Yamada brought to Tokikaze's mind an image of a timid figure. Despite being a Seated Officer, Hanatarō Yamada was often bullied by lower-ranked members, lacking the dignity of his position.

Considering this was the Fourth Division, it seemed there were specific internal dynamics.

Tokikaze's strongest impression of him wasn't his personality but his Zanpakutō—Hisagomaru.

It could absorb damage when healing an opponent and then release accumulated damage in one powerful strike, potentially killing even a Gillian-class Hollow.

A very potent Zanpakutō.

It perfectly embodied the concept of becoming stronger as the battle progressed.

Hanatarō Yamada might be better suited for the Eleventh Division, given his Zanpakutō's capabilities.

However, his timid nature made him unsuitable for combat.

It's a wasted talent, really.

"I've heard of him. Isn't he still a squad member?" Tokikaze asked. "If he were braver, he could become a pillar of the Fourth Division."

Yamada Seinosuke was slightly surprised his brother was so well-known. Though he often spoke harshly about Hanatarō Yamada, he genuinely cared for his brother's growth.

Hearing Tokikaze's assessment sparked new thoughts in him.

"Do you have any suggestions, Captain Tokikaze?"

Tokikaze laughed. "It's simple enough; it depends on whether you can be tough on him."

"Do you know Ikkaku Madarame? He's under my command at the Ninth Division, conducting hellish training for our members. He might not be extraordinarily strong, but he's quite capable as an instructor."

"Hand Hanatarō Yamada over to him for training. In time, you'll see a new Hanatarō Yamada."

Yamada Seinosuke was intrigued by the idea.

Hanatarō Yamada's timid nature had long been a headache for him. If it could be changed, his brother's future would be much brighter, even if not extraordinary.

"Alright, I'll leave it to you, Captain Tokikaze!" Yamada Seinosuke gritted his teeth and decided for his brother.

Tokikaze smiled subtly, hiding his accomplishment.

Meanwhile, Hanatarō Yamada, sweeping the streets of the Fourth Division barracks, suddenly shivered. Looking around, he found nothing unusual.

Yet, he couldn't shake the feeling that an immense wave of malice was heading his way…