Under Katori Nanatsuki's precise control, the Hollow Poison was continuously separated and expelled. Unohana Retsu's arm was recovering rapidly.
Once the Hollow Poison was drawn out, the skin on her arm gradually returned to its former jade-like smoothness.
Despite being a master of Zanjutsu, Unohana's hands bore no calluses whatsoever.
As Nanatsuki held her hand, he could barely feel any warmth. It was like holding a piece of cool, perfectly rounded jade.
In the end, Nanatsuki successfully removed every trace of Vasto Lorde-grade Hollow Poison from Unohana's body.
"Katori-sensei... actually... cured Vasto Lorde-grade Hollow Poison!"
The students of the Kaido Advanced Class were stunned. Although they didn't truly understand the details of Nanatsuki's operation, seeing the extracted poison corrode right through the surgical table left them with a concrete impression of how deadly it was.
A Zanjutsu instructor had solved a problem that even the Kaido instructors couldn't handle—this completely astonished the students.
The Kaido Department instructors couldn't wrap their heads around it either. How could this new teacher, Katori-sensei, who possessed such high-level Kaido, end up teaching Zanjutsu instead?
Department Head Yamada felt deeply ashamed. He had previously questioned such a capable Kaido practitioner. The Kaido prowess that Katori Nanatsuki displayed left him utterly embarrassed.
"Katori-kun, it seems I misjudged you. I never realized you were a Kaido genius," Unohana remarked in awe.
She too was shocked by Nanatsuki's display of Kaido.
His skill had nearly reached her own level!
She had personally taught NanatsukiKaido years ago, so she clearly remembered how his abilities were back then.
His progress was astonishing—enough to be called a prodigy of Kaido!
Unohana was now seriously tempted to poach Katori Nanatsuki for her own division as her lieutenant.
Currently, the Fourth Division's lieutenant position was vacant. The existing seated officers all had rather average Kaido talent. That's why Unohana came to the Kaido Advanced Class—to scout for promising candidates.
"In order to heal Batsu'unsai's Spiritual Pressure Core, I've been diligently training in Kaido," Nanatsuki replied honestly. He had never stopped studying it.
"Ara~ Katori-kun, you're so charming when you're capable. Why don't you come with me to the Fourth Division right now and become my lieutenant?" Unohana said with a soft smile.
She was almost ready to wrest Nanatsuki away from Batsu'unsai as her personal successor. His dual talents in Zanjutsu and Kaido made him an ideal match for her abilities. There were very few Shinigami like him in all of Soul Society.
"Thank you for your kind offer, Captain Unohana, but I'm not yet qualified to be a lieutenant. Besides, I truly enjoy teaching at the Shin'o Spiritual Arts Academy. Its students are the future of Soul Society. Being able to teach and pass on knowledge and technique is a deeply rewarding job—I love it," Nanatsuki said politely but firmly.
Though the lieutenant position was tempting, he wouldn't abandon his post at the Academy for it. It was a key part of his plan to grow stronger.
Unohana blinked, slightly surprised by his sincerity.
The students and Kaido instructors present were also moved. He had just turned down the opportunity to become Fourth Division's lieutenant—all because of his passion for teaching. What dedication!
"That's truly a shame..." Unohana said, deciding to try again another time.
"But... now that I think about it, the poison's already been cleansed. Katori-kun, are you planning to let go of my hand anytime soon?" she asked with a teasing smile.
Normally, holding hands with the original Kenpachi would be no different from suicide.
"Ah... I got a bit carried away while talking..." Nanatsuki felt a chill run through him and reluctantly released the beauty's hand.
"Katori-sensei, I had no idea your Kaido skills were this advanced. I was blind before and acted rudely. Please, transfer to the Kaido Department! I plan to retire in a few years—if you come to Kaido, I'd absolutely recommend you as the next department head!" Yamada declared. Knowing full well he couldn't compare, he even addressed Nanatsuki formally despite being much older.
"That's right. With such talent, Katori-sensei is wasted in the Zanjutsu Department," added Instructor Kobayashi.
"You flatter me. I think the Zanjutsu Department suits me just fine," Nanatsuki replied. He still taught both the Zanjutsu Advanced Class and the Sixth-Year class, and he wasn't about to give up teaching them—not before taking Shihōin-san as his student.
"This... staying in Zanjutsu would be such a waste of your Kaido talent!" Yamada protested.
"Department Head Yamada, Katori-kun's swordsmanship is actually quite good too. It's not a waste at all," Unohana interjected.
"Then the Zanjutsu Department is really lucky—to have recruited someone like Katori-sensei," Yamada said, backing down.
"That concludes today's lecture," Unohana announced.
She still had to look into something. That vial of Vasto Lorde-grade Hollow Poison hadn't been the intended teaching material.
She had personally prepared the Hollow Poison last week, and now something completely unexpected had occurred.
And that vial had been stored in the Fourth Division's reserves—where no outsiders should have had access.
She needed to investigate. There might be a traitor in the Fourth Division.
After the lecture, Nanatsuki left along with the others.
Before leaving, Unohana told him again, "Until we find someone more suitable, the position of Fourth Division lieutenant will be held open for you. If you ever grow tired of teaching, you'll be warmly welcomed."
Yamada added, "The Kaido Department feels the same. If Katori-sensei is willing to transfer, I'll absolutely recommend you as the next Kaido Department Head!"
Nanatsuki replied, "Thank you both for your faith in me. But for now, I have no plans to leave the Zanjutsu Department."
Yamada thought for a moment and then said, "Would you have time to give a lecture to the Kaido Advanced Class? We sometimes invite Fourth Division experts to speak. With your skill, Katori-sensei, I'd be honored to have you share your knowledge."
That piqued Nanatsuki's interest. Giving a guest lecture might trigger a first-time teaching reward from the Kaido Advanced Class, just like when he first taught the Zanjutsu Advanced Class, which had yielded great returns.
Nanatsuki agreed, "Feel free to arrange it, Department Head Yamada. I'd be happy to share what I know with the students."
"Then the Kaido Advanced Class is truly blessed!" Yamada beamed. "I'll make sure it doesn't conflict with your current schedule."
After the group departed, Instructor Kobayashi said admiringly, "Katori-sensei is amazing. Both Captain Unohana and Department Head Yamada value him so highly!"