When Sasuke felt the changes in himself, his feelings were much like Naruto's.
He was stunned himself.
All he had done was keep moving forward through that void...
Even Sasuke wasn't sure how long he had been walking.
The only thing he knew was that he had to keep going.
Back then, Sasuke had seen Naruto and Gaara's backs in his mind.
The two walked farther and farther ahead.
No matter how desperately Sasuke chased them, their figures still slowly faded.
Under those circumstances, their vanishing backs became Sasuke's greatest motivation.
That was when his Two-Tomoe Sharingan evolved into the Three-Tomoe Sharingan.
To the outside world, Sasuke had merely spent six days training with his eyes closed.
But...
Sasuke himself knew that at least a year had passed inside Uchiha Kazama's genjutsu space... perhaps even longer.
"Where's our teacher?!"
Sasuke took a deep breath, suppressed his excitement, and slowly spoke.
"Teacher had something to take care of. He hasn't come back yet."
"Sasuke, can you use more advanced genjutsu now?!"
Naruto looked at Sasuke curiously.
After all, during his previous fights with Sasuke...
The few genjutsu Sasuke had mastered had given Naruto plenty of trouble.
Unless he enveloped himself in Kurama's chakra, he couldn't fight properly at all.
"With my current pupillary power, I can cast multiple genjutsu at once. I should also be able to train in the genjutsu I didn't meet the requirements for before."
"And I think there have been some other changes, too."
Sensing the changes in the energy within his body, Sasuke Uchiha slowly raised his hands.
"Fire Release: Great Fireball Technique!"
As he formed hand seals, a massive fireball appeared in an instant.
When the huge fireball struck a nearby boulder, it melted straight through it.
Boom!
A tremendous explosion followed.
The great fireball