The final control line overlapped completely with the chakra in his heart.
It had no color.
Nor did it have an edge that a Chakra Blade could pry open.
If Black Zetsu's three tendrils had not already been sealed, the Medical Squad would not even have been able to confirm that it still existed.
With every beat of Obito's heart, the control line contracted.
It was drawing on his very life.
To sever it, his body would have to reject Black Zetsu's core as part of itself while his heart continued to beat.
"Third-stage authorization," the Land of Rivers Witness said.
Only two seals lit up at the edge of the stone platform.
Konoha's medical authorization remained in place.
The Land of Rivers Suspension Seal was unchanged as well.
But the final authorization, the one belonging to Obito, had yet to appear.
Half of Black Zetsu's face emerged from the wound in his back.
"You can't reject your own heart."
"Without the white tissue, you would have died at Kannabi Bridge long ago."
"Severing me means severing the part of you that survived."
He was not entirely lying.
The right half of Obito's body was still supported by white tissue.
The black core had long since grown into the repair network as well.
But saving a life did not give the savior ownership of every choice that life would make afterward.
Obito raised his right hand and pressed it against his chest.
The third Authorization Seal lit up.
"Begin."
Kakashi immediately concentrated the ocular power in his left eye.
All three outer anchoring rings stabilized at once.
Obito did not aim his right eye at Black Zetsu.
He placed Kamui's focal point around the control line, letting the spatial distortion form an extremely narrow isolation band.
The left eye anchored