Kakashi's gaze shifted slightly, and he instantly understood what Naruto meant.
He recalled what had happened before: when Uchiha Itachi and Kisame Hoshigaki infiltrated Konoha, they had ultimately been discovered and forced their way out using Perfect Susanoo.
Perfect Susanoo...
Kakashi repeated the words silently.
Before Naruto told him that his eye was actually already a Mangekyō Sharingan, Kakashi had always believed the left eye Obito gave him still had only three tomoe.
As someone who possessed a Mangekyō Sharingan and had used its dōjutsu, Kakashi knew just how terrifying its drain could be.
Especially something as enormous as Perfect Susanoo-its burden on the user's body and ocular power was staggering.
Even if Itachi's Perfect Susanoo was much smaller than Sasuke's, there was no question about the toll it took.
It did not merely consume chakra. It directly drained the user's life force.
And Uchiha Itachi...
Kakashi's gaze also fell on the haggard figure in the courtyard.
Given Itachi's dreadful condition-sickly and frail, with unstable chakra and a body riddled with hidden injuries-the fact that he had forced himself to activate Perfect Susanoo without dropping dead on the spot, and even managed to escape afterward, was already a miracle of willpower and the strength of his bloodline.
Through close-range sensing and observation, Naruto could now confirm that forcing out that ultimate technique had dealt an almost devastating blow to Uchiha Itachi's already ravaged body.
Overtaxing the Mangekyō Sharingan's power had accelerated his physical collapse and worsened his illness.
Itachi was only eighteen this year, but judging by how weak his life force had become, Naruto estimated that he was already close to death. It was only a matter of time before his life burned out.
Had events followed their original course, Itachi would probably have succumbed to his illness at