Perhaps an Exceptionally Powerful Kekkei Genkai

Wood Release, Ice Release, Lava Release, and so on, all work in this way. Two types of Chakra fuse under the influence of special Bloodline Factor, thereby generating even more powerful energy.

Similarly, the fusion of Chakra variations still puts a manageable strain on the body, and since the power is primarily applied to external forces, the physical impact is minimal.

However, the Shikotsumyaku is different.

"The Shikotsumyaku) Kekkei Genkai a rather unique form of existence. Its ability to control bone growth, calcium concentration, and so on, goes beyond just Chakra fluctuations. Bones support the body, and bone marrow, the organ that produces blood, is also affected... Every time Kekkei Genkai is used, the power spreads, and the first thing affected is one's own body..."

Does this mean that Kekkei Genkai itself is Bloodline Disease?

Rokuro Kaguya's hands, gripping the table, showed fine blue veins that bulged, and his breathing became rapid.

Similarly, Tong sat upright, not daring to breathe loudly, her eyes fixed on the tea leaves in her teacup, her ears straining as if afraid of missing a single word.

"Yes, and the Bloodline Disease isn't caused by a flaw in the Kekkei Genkai, but rather by the awakening of the true power of the Shikotsumyaku Kekkei Genkai. It's just that the body can't handle that near-perfect power, thus falling into a state of collapse. It's like Jinchuriki has lost their Tailed Beast; one's onset is slow, while the other's effects are very fast..."

Katsuki revealed his guess without reservation.

Memories of his past life flashed through his mind like a film reel, with the scene of Kaguya Otsutsuki using the All-Killing Ash Bones appearing incredibly clear.

His intuition told him that Kaguya Clan's Shikotsumyaku was definitely related to that move. Her body, which was suffering from Bloodline Disease and gradually decaying until death, was so similar to the situation when she was hit by the All-Killing Ash Bones.

... Are they descendants of the Six Paths again? He muttered to himself. The entanglements and conflicts in the Shinobi World countless years had turned out to be nothing more than a family drama, a struggle between a mother and her rebellious son that had lasted for thousands of years.

It's not funny at all.

Katsuki had absolutely no interest in such a bloody family drama.

"In short, based on my speculation, Shikotsumyaku is an extremely powerful Kekkei Genkai. If it could be fully awakened, it might... be a power comparable to Wood Release and the Sharingan."

Katsuki pinched her chin, estimating the difference.

Even among Kekkei Genkai, there are differences in strength. For example, Wood Release and Sharingan are almost universally recognized as top-tier Kekkei Genkai; just hearing their names can instill fear in the timid.

The remaining Kekkei Genkai equal in strength, with the Shikotsumyaku being one of them.

"I dare not hope for anything comparable to Wood Release and Sharingan. As long as the Bloodline Disease can be resolved, it will already be a blessing. If I am too greedy, I am afraid I will be punished by the heavens." Rokuro Kaguya shook his head and smiled bitterly.

Ninjas are driven by a thirst for power; the desire for greater power is an instinct of every ninja.

Although Rokuro Kaguya had one foot in the grave, his mind was clear. More than greater power, what the Kaguya Clan needed was a cure for their Bloodline Disease.

"Liulang, you've worked hard too!"

Katsuki looked at Rokuro Kaguya and sighed.

"... It's not hard work, it's all for the sake of the clan. This is... my responsibility, the responsibility I must fulfill as the clan leader."

Rokuro Kaguya loosened his grip on the table with his right hand and clenched it into a fist.

"Responsibility, huh? You're a good clan leader, much more qualified than me." Katsuki's lips curled up, and she chuckled softly. "Rokuro, don't be so anxious. As long as my deduction is proven correct, the treatment won't be too difficult. The reason our previous research hadn't made progress was because we couldn't grasp the cause of the disease; we simply didn't know where to begin."

"Ta-da..."

Rokuro Kaguya suddenly stood up, his footsteps on the tatami mats sounding heavy. He walked around the low table and turned to Katsuki's right.

He knelt down solemnly, and even performed a full dogeza (a traditional Japanese kneeling posture)!

"I beg you, Lord Katsuki, whether this succeeds or fails, the Kaguya Clan will always be the Uzumaki Clan's most loyal ally."

"Lord Katsuki, I'm begging you."

Tong hurriedly stood up and knelt down as well.

"There's no need for such exaggeration, Liu Lang, Tong Mei Mei. I don't like to give up halfway through things. Finishing what I start is my guiding principle."

"Shikotsumyaku... All-Killing Ash Bones..."

After seeing off Rokuro Kaguya and Kaguya Hibiki, Katsuki sat under the eaves, staring blankly at the sky.

Mizuki's fervent research into the Shikotsumyaku Bloodline Disease wasn't driven by genuine Katsuki, but rather by sheer curiosity. The Shikotsumyaku of the Kaguya Clan, a power lost to time in her previous life, possessed a unique fighting style and distinctive abilities, coupled with its intricate connection to Kaguya Otsutsuki.

Curiosity is like a flood that has broken through the dam and is overflowing.

"That's interesting! Really interesting!"

"What's interesting?"

Kushina walked briskly down the corridor.

"Sister, what brings you here?"

"What? You're making it sound like I can't come. Don't forget, my surname is also Whirlpool."

Kushina glared at her.

"Anyway, you're going to change your surname soon, aren't you?" Katsuki muttered under her breath, then shrank back, bracing herself for a beating.

······

"Huh?"

Gone was the iron fist that usually wielded her power. Katsuki stared in astonishment at Kushina standing in the corridor, her face flushed, nervously fidgeting with the hem of her clothes.

"... Sister, what... what did that bastard Minato do?"

Katsuki suddenly jumped up, her fists clenched, her killing intent surging like Dotō.

"N-no... I didn't do anything..." Kushina's face turned even redder. She looked away shyly at Katsuki, her head practically steaming, and stammered, "It's just that... that... Minato, he..."

What did he do?

Katsuki's fists clenched so tightly they cracked.

"Um... um... he proposed to me."

"He proposed? Hmm... This day has finally come!"

Katsuki loosened her fist, and the surging aura around her suddenly subsided.

"I thought something amazing had happened, like I was going to be an uncle or something, but it turns out it was just a request..."

"Bang!"

The fist made intimate contact with the left cheek, and Katsuki was sent flying, crashing through the courtyard wall and plunging headfirst into the bluestone floor.

"Ptooey, ptooey, ptooey!" Pulling her head out of the ground, Katsuki wiped her face and walked back, looking utterly bewildered. "Sis, when did you become so strong? Is this superhuman strength?"

"I ran into Lady Tsunade while shopping and learned a move from her... Don't try to change the subject, what... what were you saying just now? Uncle... Uncle... Uncle..."

Kushina's tongue seemed to be tied in knots, unable to utter a single coherent word. (To be continued)