Amaterasu and the Severed Arm

When the Raikage's fist came crashing down, Sasuke's Sharingan caught it.

Three tomoe spun rapidly within his crimson eyes. The lightning release chakra wrapped around the Raikage's body became a dazzling blue streak in his vision—astonishingly fast, but not impossible to follow. Sasuke twisted aside, and the Kusanagi Sword skimmed past the Raikage's fist, its blade screeching as it scraped against the lightning release chakra.

But the Raikage had more than one fist.

The first punch grazed Sasuke's shoulder, and the second followed immediately after, as swift as real lightning. Sasuke had no time to dodge and could only cross his arms to block. In that instant, he felt as though a mountain had slammed into him—not figuratively, but truly like a mountain. Lightning Release Chakra pierced through his defense, and every nerve in his arms screamed. His entire body slid backward, his shoes carving two charred tracks into the ground, until he crashed into a corridor pillar and finally stopped.

"Sasuke!" Karin screamed from behind him.

Sasuke did not turn around. His arms trembled, the skin between his thumbs and forefingers split open, and blood dripped down his fingers. But he did not fall. The Mangekyō Sharingan slowly formed in his left eye—the three tomoe began to rotate, accelerate, merge into one, and finally transformed into an entirely new pattern.

These were the eyes he had gained after killing Itachi.

The Raikage stopped his pursuit and narrowed his eyes at the unfamiliar pattern in Sasuke's left eye. "Mangekyō Sharingan?" There was a hint of surprise in his voice. "The same eyes as Itachi?"

Sasuke did not answer. His left eye began to ache sharply, his vision blurring for an instant before quickly clearing again. The Mangekyō's power surged within him like a beast trapped in a cage, desperate to