After devouring the plump, juicy fish, Da Bai suddenly spread its wings and let out a high-pitched, resonant cry that echoed through the sky, audible for miles.
"Hmm?" Umino Yoru frowned slightly, sensing a faint, almost imperceptible ripple of chakra.
Screeeech!
Da Bai flapped its wings vigorously, stirring up swirling gusts of wind that sent leaves scattering in all directions.
"This is—"
Noticing Da Bai's unusual behavior, Umino Yoru immediately activated his Subsonic Radar Technique to enhance his perception.
At that moment, Da Bai's blood and energy surged violently within its body, its breathing becoming rapid and intense.
With every inhale and exhale, its rhythm synchronized with the wind currents outside, forming a strange, harmonious frequency—even establishing some kind of inexplicable connection.
Soon, a faint, azure-colored Wind Release chakra condensed near Da Bai's heart.
"Da Bai has refined chakra!"
Umino Yoru was overjoyed. Although Da Bai was a high-level summoning beast—a fledgling Desert Giant Falcon with noble lineage and even signs of ancestral reversion—it had still been at risk of premature death before refining chakra.
Now that it had successfully refined chakra, it wouldn't be completely immune to illness, but unless it suffered severe injuries, it would no longer die without cause.
Moreover, with Da Bai's current size advantage and newfound chakra, its survivability had skyrocketed.
In terms of combat power, it far surpassed the Genin-level Water Bat he had previously contracted.
Dealing with ordinary Genin wouldn't be a problem.
Even against a Chūnin, Da Bai's bullet-like speed would allow it to hold its own for a while, and its escape ability had greatly improved.
Screeeech!
After refining chakra for some time, Da Bai exhausted its energy, then spread its wings and flew over, affectionately nuzzling Umino Yoru 's arm with its head, its eyes filled with expectation.
Clearly, refining chakra had consumed a massive amount of energy, and now it was hungry again, hoping for Umino Yoru to feed it.
"Heh." Umino Yoru chuckled knowingly and patted Da Bai's head.
Then, he pointed at the river and lightly tapped the water's surface with his finger.
"Shock!"
He unleashed a Subsonic Shockwave.
Within seconds, a large number of freshwater fish floated to the surface, belly-up.
Screech!
Da Bai cried out joyfully, swooping down to snatch the fish from the water and carry them to shore, where it began feasting ravenously.
With over a hundred pounds of fish, Da Bai would have enough to eat for the entire day. Satisfied, Umino Yoru left it to its meal and resumed his training.
"The 6-Seal Water Dragon Bullet Technique is basically mastered. Now it's time to focus on the Shadow Clone Shuriken Technique."
When learning ninjutsu, it was best to start with the easier ones before tackling the harder ones.
He had initially assumed that the Shadow Clone Shuriken Technique, an A-rank ninjutsu, would be the most difficult due to its high rank. But to his surprise, he found it much simpler than the B-rank Water Release: Water Dragon Bullet Technique.
The prerequisites for the Shadow Clone Shuriken Technique were:
Chakra reserves Hand seal speed Transformation proficiency Shadow Clone experience
The training difficulty was indeed high—so much so that many Jōnin might not even meet these strict conditions.
But for Umino Yoru , they were all perfectly fulfilled.
Chakra reserves? Barely sufficient. Hand seals? Five seals per second—on par with Kage-level shinobi. Transformation? He had built his foundation on it; even a member of the Inuzuka clan wouldn't dare claim superiority. Shadow Clone experience? No need to explain—nine shadow clones were still training beside him.
Whoosh!
Umino Yoru pulled a shuriken from his pouch and hurled it forward.
Then, his hands blurred as he formed the eight hand seals at five seals per second:
Boar → Dog → Dragon → Rat → Dog → Boar → Snake → Tiger.
"Shadow Clone Shuriken Technique!"
Instantly, the single shuriken in midair multiplied like an exploding beehive, splitting into nearly a hundred identical copies.
The dense barrage of shuriken poured down like a waterfall, striking a tree thirty paces away. Wood splintered violently under the assault.
Some shuriken even pierced through the first tree and embedded themselves in a second one behind it.
"Tch…"
Umino Yoru sucked in a sharp breath.
A-rank ninjutsu truly lived up to its terrifying reputation.
The sheer density of the shuriken made it not only devastating in power but also wide in coverage.
Its practicality was undeniable.
No wonder even Kage-level shinobi like Hiruzen Sarutobi and Minato Namikaze frequently used this technique—it had its unique advantages.
"Cough, cough…"
Before Umino Yoru could recover from his amazement, he realized his chakra had been completely drained.
Ever since mastering the Akimichi Digestion Technique, he hadn't experienced such severe chakra depletion in a long time.
"As expected of an A-rank ninjutsu—the chakra consumption is no joke."
While the Akimichi Digestion Technique allowed for rapid chakra and stamina recovery, it couldn't break through his body's natural chakra capacity limit.
It was like a rechargeable battery—it could keep refilling, but the battery's size remained fixed.
Objectively speaking, due to his reincarnation, his spiritual energy had greatly increased. His chakra reserves weren't at Jōnin level, but they were noticeably higher than most Chūnin.
Additionally, after mastering the Akimichi Digestion Technique, he had replenished all the deficiencies in his body from previous years, further boosting his chakra.
If we used Kakashi Hatake's chakra at his debut as a benchmark (where "1 Kaka" was enough for about 4 A-rank ninjutsu), then one A-rank ninjutsu consumed roughly 0.25 Kaka.
Since Kakashi's reserves were twice that of an average Jōnin, Umino Yoru estimated his own chakra to be between 0.25 and 0.5 Kaka.
A more precise estimate would be slightly above 0.3 Kaka.
Most Tokubetsu Jōnin (Special Jōnin) had around this amount. For a civilian-born shinobi like himself, this was already quite impressive.
"I must find a way to solve my severe chakra shortage soon. Otherwise, after using just one A-rank ninjutsu, I'd be a sitting duck."
To quickly find a method to increase his chakra reserves, he stopped grinding the chakra-hungry Shadow Clone Shuriken Technique and instead pulled out the Wind Release Chakra Development Scroll to study.
"What? How could this be?!"
The deeper he read, the more he realized—just as Akimichi Torifu had said—developing a second chakra nature did not inherently break the body's chakra capacity limit.
"No wonder Kakashi, despite mastering five chakra natures, still struggled with chakra exhaustion. It wasn't just because of the Sharingan."
After finishing the scroll, he didn't doubt its authenticity. After all, even Kakashi, with his elite lineage (his father being the Kage-level White Fang), had chakra problems.
If developing additional chakra natures truly increased one's reserves, Kakashi—with five natures—should have had vast chakra reserves. Instead, he was still famously low on chakra.
"Guess I'll have to find another way."
Though disappointed, Umino Yoru wasn't disheartened. The shinobi world had many methods to increase chakra—he just needed to seize the right opportunity.
With renewed determination, he resumed training the Shadow Clone Shuriken Technique while his nine shadow clones worked on Water Release, Three Basic Techniques, Mechanized Puppetry, and taijutsu.
Whenever a shadow clone ran out of chakra, he dispelled it, summoned a new one, ate several pounds of food to recover, and absorbed the training experience.
After half a day of training, while assimilating a Transformation Technique memory, he suddenly noticed something strange.
He immediately activated the Basic Body Flicker Technique and rushed to Da Bai's side.
"Huh?" Umino Yoru was shocked.
In just half a day, Da Bai had undergone a dramatic transformation.
It had devoured nearly a hundred pounds of fish, its size had doubled, and its Wind Release chakra had multiplied several times over.
Earlier, while practicing the Beast Mimicry Transformation, his shadow clone had observed peculiar phenomena within Da Bai's body.
He quickly activated the Subsonic Radar Technique for a more detailed examination.
"Seven Heavens Breathing Method?"
"Akimichi Digestion Technique?"
"Or Tiger and Leopard Thunder Resonance?"
The more he studied, the more astonished he became. Da Bai's current state resembled Shī, the Seven Heavens Breathing Method created by Suna's Shī, which used oxygen absorption to activate cells throughout the body.
But there were differences—Da Bai wasn't just absorbing oxygen but other elements as well.
After cellular activation, Da Bai's digestive system was processing food at an incredible speed. While not as extreme as the Akimichi Digestion Technique, it was still several times faster than a normal creature's metabolism.
Once the food was digested, Da Bai's cells seemed to "breathe" in a unique rhythm, reminiscent of the Tiger and Leopard Thunder Resonance from his past life's novels.
This allowed it to gradually absorb the digested nutrients and some mysterious factor from the air into its cells.
No matter how much he researched, he couldn't fully decipher the mystery.
So, he activated the Subsonic Radar Technique again, carefully observing Da Bai's internal changes, then mimicked its breathing rhythm to learn from it.
"Huh?" The moment he started imitating it, he noticed his food energy was being consumed slightly faster than usual.
Though the difference was minimal, it proved that this training method was effective.
The extra energy wasn't vanishing—it had to be stored somewhere in his body.
"Tch…"
After just thirty minutes of imitation training, his entire body tingled as if countless ants were biting him.
Clearly, the cellular activation process, combined with absorbing the mysterious factor and food energy, was placing a heavy burden on his body.