The first examination after the copy was sealed away was not a search for the caster's name.
The Medical Squad first answered a more fundamental question.
Was the black line beside the heart actually an ordinary catheter keeping Obito alive?
Only half the line remained in the record.
But it differed from the medical diagrams preserved in the underground room.
Life-support catheters would branch along the blood vessels and chakra pathways, with at least two return-flow connections.
The black line, however, emerged directly from the center of the heart, passed through three closed nodes, and finally pointed outside the body.
It was not a conduit.
It was a restraint.
The Sealing Squad enlarged the diagram and found faint traces of a reverse-oriented formula around the nodes.
The formula did not actively release chakra under normal circumstances.
Only when the Patient's power touched a forbidden pathway would it use the heartbeat to tighten itself.
Structures like this had once been used to restrain prisoners during the Warring States period.
The caster did not need to control them constantly.
Every breath the Patient took supplied the cursed seal with the power to sustain itself.
The catheter connections in the underground room were also reexamined.
The same three closed nodes remained on the inside of a copper connector.
On the surface, it connected the white tissue to the right half of the body, but its inner layer concealed a thin tube leading to the heart.
When Obito had been unable to move and forced to rely on repairs, the restriction had likely entered his body along with the white tissue.
He might never have known that the life-support tube had a second function.
Danzo demanded that the discovery be recorded as "the Masked Man is under Madara's complete control."
Kakashi was the first