At the Katori-ryu Dojo, Shiba Isshin had already changed into the dojo's uniform. Four small bells were tied to his belt and sleeves.
Wielding a massive flagfish wooden sword, he repeatedly swung it, the bells on his body ringing with each motion.
"Raise it a bit higher. Did you forget how to practice suburi?" Katori Nanatsuki tapped the back of Isshin's hand with his wooden sword.
"Sensei, this is too hard! The wooden sword's heavy, and I have to constantly control the bells with my Reiatsu..." Isshin complained, nearly wailing.
"You'll need time to adapt. This isn't something you can master overnight," Nanatsuki replied calmly.
Since Isshin had a stronger foundation than most disciples when they started, Nanatsuki held him to a higher standard.
He had him jump straight into advanced Reiatsu control training.
It was Isshin's first time encountering this type of training, so it would take a while to get used to it.
"Can't you just teach me sword techniques already?" Isshin asked.
"You're too impatient. A restless heart makes for a distracted blade. Training the heart comes first." Nanatsuki lightly knocked the top of Isshin's head with his sword. "Katori-ryu's Reiatsu control method is already considered fast. A powerful mastery of Reiatsu control is the foundation of true strength. With it, you'll outshine others of equal Reiatsu."
Isshin shrank his neck and quickly said, "Fine, I'll train..."
Nanatsuki moved on to check the other disciples' progress.
After the live-blade sparring session, Nanatsuki had assigned new training tasks to the group of four led by Azashiro Kana.
Kana's right hand still needed time to recover, so Nanatsuki had her start learning Finger Sword, a technique that could be practiced with the left hand.
Hirako Shinji was training in Kidō.
He had a deep interest in Kidō and didn't want to specialize only in swordsmanship.
Muguruma Kensei was practicing the sword technique Windchase. Combined with his Zanpakutō's effect, using this technique would greatly enhance his power.
Kobane Jin'emon was training in the Flowlight sword technique.
As for Aizen Sōsuke, he had already completed the sword technique training previously assigned to him:
[Disciple Aizen Sōsuke has completed a sword technique training. Reward calculated.]
[Received reward: 5,000 General Ability EXP]
[Received reward: Sword Technique - Wave Break (Beginner Level)]
Aizen had already learned Wave Break, and this training's feedback reward happened to be that same technique.
Just as Nanatsuki was considering what to teach Aizen next, the boy suddenly made a request:
"Sensei, can you teach me Kaido?"
"You're interested in Kaido?" Nanatsuki raised an eyebrow.
Aizen wouldn't show interest in Kaido without reason. Since Kaido and medical knowledge were closely related to spiritual anatomy, Nanatsuki figured Aizen must be curious about spiritual bodies, which prompted his desire to learn Kaido.
"I think Kaido is really practical. If I can master it, I might be able to use it in critical moments someday," Aizen said with a smile.
He often sneaked into Seireitei at night and infiltrated noble estates to read their private collections.
After weeks of reading, he had uncovered many secrets from those books. He was no longer ignorant of the world.
Now, he had grown curious about something deeper—the essence of a Shinigami.
"Very well, I'll teach you Kaido," Nanatsuki nodded.
Even if he didn't intervene, Aizen would eventually pursue the path of spiritual research. Nanatsuki himself had similar aspirations. Instead of letting Aizen delve into such things unsupervised, it was better to guide him early. Once Aizen grew strong enough, he could assist in his research.
[Current training mission added: Instruct Aizen Sōsuke in Basic Kaido Training (In Progress)]
A week later, Nanatsuki received a message from Ushada Hakugen, the head of the Kido Advanced Class. The lecture schedule was finalized, and Nanatsuki was invited to give a guest lecture.
"Professor Katori, we heard that during the Karakura Town incident, you used Hiryū Gekizoku Shinten Raihō and took down a Menos Grande in a single strike! Can you teach us that spell?" one of the students asked eagerly.
"Hiryū Gekizoku Shinten Raihō is a high-tier Hadō spell. For your current level, it's too advanced," Nanatsuki said with a gentle smile. "Kidō is incredibly diverse, with a huge number of spells suited to all kinds of situations. Don't fixate too much on pursuing only high-tier techniques."
"The power of Kidō depends on the user. Today, I'll share some practical Kidō techniques that will help you apply them more effectively in real combat."
In the lecture, Nanatsuki taught the students about Chant Abandonment and Post-Chanting, as well as real-world applications of Kidō.
When the class concluded, he received his reward for teaching his first Kido Advanced Class session:
[First-time Kido Advanced Class lecture completed. Bonus rewards granted:]
[Acquired Trait: Dual Chanting]
[Received: 10,000 General Ability EXP]
[Random Skill Mastery +1] x2
[Gained: 3 Disciple Binding Slots]
Nanatsuki glanced at his Status Interface and examined the new trait:
[Dual Chanting: You have developed a unique understanding of Kidō. You can stack the chants of two Kidō spells and combine them into a single cast.]
Dual Chanting was an extremely advanced Kidō technique, one that only highly skilled Shinigami could master.
Besides the trait and general EXP, the two bonus mastery upgrades were both applied to Finger Sword, raising its proficiency to Mastery level.
After reaching mastery, Nanatsuki mentally reviewed the Finger Sword techniques, and suddenly, inspiration struck.
He raised two fingers. Arcs of lightning danced along their tips.
Sparks burst from the lightning, instantly forming red flame.
Lightning and flame twined together, finally merging into golden thunderfire.
Finger Sword: Thunderfire Wild Blaze!
He had successfully combined Thunderfire Wild Blaze with Finger Sword!
By casting Thunderfire Wild Blaze in Finger Sword form, even though his physical body didn't receive the usual buff from the golden flame, the casting speed was significantly increased. And just like Flowlight, it could be used for ranged attacks.
Nanatsuki could feel the Reiatsu Blade surging with Reishi between his fingers—the intense vibration hinted at impressive power. His hands itched.
He wanted to test how powerful it had become.
His Reiatsu had grown a lot recently. He really needed a solid fight to stabilize and refine his growth.
He went over his possible sparring options.
The disciples and teachers at the academy were out—none of them could give him the pressure he needed.
Katori Batsu'unsai's physical condition wasn't suitable.
Kyōraku Shunsui definitely wouldn't agree. With his easygoing attitude, he wouldn't bother to lift a finger.
Hikifune Kirio likely wouldn't accept either—she just wasn't a battle-oriented person.
Genryūsai Shigekuni Yamamoto... Nanatsuki shook his head. That would just mean getting beat up one-sidedly.
Unohana Retsu, though—she might be the only Captain who would spar with him seriously.
And so, a bold idea popped into his mind:
'Maybe I should go challenge Unohana to a duel.'