After learning the whereabouts of the surviving Senju child, Kabuto and Sasuke left the village. Before leaving, Kabuto also told the villagers how to maintain their water supply.
On the mountain path, Sasuke mused, "Chishin Senju was the First Hokage's son, wasn't he? To think someone like that died of an illness..."
Kabuto Yakushi adjusted his glasses. "Medical Ninjutsu was originally used for emergency treatment of injuries sustained in battle. It wasn't particularly effective against disease. But Lady Tsunade took Medical Ninjutsu to new heights. Even internal lesions can be removed through surgery, though only in the early stages..."
"Once the lesions spread throughout the body, even Medical Ninjutsu on Lady Tsunade's level can't save the patient."
"I imagine... Chishin Senju had that sort of incurable disease. It's a calamity that even the strongest people struggle to overcome."
Sasuke... thought of Itachi.
He had already learned from Obito that Itachi, too, had suffered from some terminal illness.
Later, Kabuto Yakushi had given him a precise answer.
What Itachi had suffered from was viral heart disease.
It was still within the scope of what Medical Ninjutsu could treat. If Tsunade had devoted herself fully to treating him, there might have been hope of recovery.
But Itachi had long since resolved to die in his battle with Sasuke, choosing only to prolong his life with medication.
Sasuke asked, "Kabuto... you've brought so many people back with Impure World Reincarnation. Wasn't Itachi among them?"
So you've finally asked that question, Sasuke-kun?
At this point, Kabuto could only be honest. "I did bring Itachi back with Impure World Reincarnation, but he broke free of my control. It happened when Naruto came looking for us, that time I sent you away to take shelter..."
Sasuke's gaze sharpened. "In other words, Itachi is alive right now,