The Caged Bird Seal was an A-rank Curse Mark Jutsu.
Although it was A-rank,
it was different from ordinary Ninjutsu.
Curse Mark Jutsu... was extremely special and difficult to judge by normal difficulty levels.
For example, Orochimaru's Curse Mark was also A-rank.
Yet even the Third Hokage, Hiruzen Sarutobi, was unable to remove it.
The Caged Bird Seal was even enough to render everyone below Six Paths Level helpless.
No...
Even Six Paths Level powerhouses would be unable to break the Caged Bird Seal as long as they could not condense Truth-Seeking Orbs or had not mastered the Power of All Things.
But the times had changed, and the version had been updated.
Hyuga Sho had become a Six Paths Level fighter.
The other Six Paths Level fighters included Kaguya-hime, Otsutsuki Toneri in Tenseigan Chakra Mode, Kamui, Ōtsutsuki Isshiki, Momoshiki, Kinshiki... and possibly Hashirama Senju.
As Six Paths Level fighters emerged like bamboo shoots after the rain,
the A-rank Caged Bird Seal was no longer enough.
At this point,
the Caged Bird Seal needed to be developed into something new.
That was... Six Paths: Caged Bird.
By using the changes of Yin-Yang Release together with the Curse Mark, it would be possible to... control Six Paths Level Ninja Weapons.
A glint flashed through Hyuga Sho's eyes.
Six Paths: Caged Bird.
This plan could also be said to have been prepared for Kamui and Six Paths Naruko.
Before he could fully research a Caged Bird Seal capable of restraining Six Paths Level targets...
some experimental operations were necessary.
And right now,
Kōseki, the female ninja from Iwagakure, could serve as the test subject for the new Curse Mark.
Thus...
Hyuga Sho activated Yin-Yang Release.
Little by little... he engraved the Curse Mark onto her...
Awakening.
When Kōseki opened her eyes,