FTE

Nemui stood upright, still sleeping, as though the attack of the previous
moment hadn’t happened. Just when Itachi noticed him swaying violently
once more, Nemui disappeared from his field of view again.

Faster than the eye could follow, Itachi danced up into the sky. Nemui’s lightning-covered arm swept through the spot where Itachi had
been standing. Itachi landed near the wall to put some space between them, and caught his enemy in his field of view. His thoughts were racing at a dizzying speed, trying somehow to analyze the phenomenon happening before his eyes.
He couldn’t use the sharingan, and all the chakra that consumed. In the
formula for an overwhelming victory, the sharingan was essential. He needed
to keep it aside until that time came.

Book of Bright Light Chapter 3 Part 1