By the hospital bed.
"No wonder he was Kakashi—a genius who'd gone to war at just a few years old. Even his brain's nerve cells were more active than other people's."
Tobitake Tonbo carefully examined Kakashi's body.
Kakashi had suffered a mental breakdown, which had led to his coma.
This was his specialty, but he still felt it would be better to leave the treatment to Tsunade. He only needed to make sure Kakashi's body was in better condition.
Why do this?
Naturally, it was to welcome Tsunade and the others as the Fifth Hokage.
To prevent Tsunade from pulling something and making him continue as Hokage, he might as well leave the credit where it belonged—to Tsunade.
Besides, Kakashi would have plenty more opportunities to lie around in the future. This one did not matter.
However, while examining Kakashi's body, Tobitake Tonbo also discovered that the Sharingan in his eye was still drawing on his chakra even now. That was also one reason Kakashi's coma had been prolonged.
Kakashi's Sharingan was completely different from Sasuke's.
There were slight differences in both its structure and chakra properties.
He also discovered why Kakashi's Sharingan could not be turned off.
It was because his body and the Sharingan rejected each other.
To the body, the Sharingan was a foreign object.
To the Sharingan, the body was also a foreign object.
But the Sharingan required chakra to sustain itself, resulting in a principle similar to the one Tobitake Tonbo had used when creating the Eye-Painting Hand.
The ratio of physical energy to spiritual energy.
When physical energy and spiritual energy were unbalanced, one would crave the other's energy.
That was how Kakashi and the Sharingan existed together now.
The Sharingan rejected Kakashi's body, yet because it had the highest proportion of spiritual energy,