Practically everyone knew Kakashi had a Sharingan. After all, Kakashi the Copy Ninja was pretty famous.
As Kakashi's student, Sasuke naturally knew too. He had even seen Kakashi copy an enemy's ninjutsu with his Sharingan, then counterattack.
He had thought it looked so cool at the time, and that sooner or later, he would be able to do it too.
After all, Kakashi only had one Sharingan, and it wasn't even his own originally. Sasuke had a complete pair.
But as Sasuke gradually came to understand the Sharingan's true power, he realized that using it the way Kakashi did was completely missing the point, sacrificing something valuable for a trivial gain.
The Sharingan itself was powerful enough. There was absolutely no need to copy anyone else's trash ninjutsu.
On second thought, though, Kakashi wasn't a member of the Uchiha Clan, so it was normal for him not to understand. It was even more normal that he couldn't bring out the Sharingan's original power.
Especially after Sasuke learned how difficult it was to awaken the Mangekyō Sharingan, he had never imagined Kakashi could succeed.
And yet, reality had slapped him in the face so quickly!
The more unexpected something was, the more likely it seemed to happen right before his eyes.
As an outsider, Kakashi had awakened the Mangekyō Sharingan using a Sharingan someone else had given him!
That was why Sasuke was so shocked-even more shocked than Kakashi had been upon seeing his Mangekyō Sharingan!
Then he heard Kakashi say gravely, "I can't control the power of this next move either, so you must resist with everything you have. Otherwise... you'll die."
With Kakashi hinting at him so seriously, Sasuke believed him. He immediately stopped holding back his chakra and Dōjutsu, pouring everything into Susanoo.
Actually, if he had simply