(Rebirth + System + Naruto + The End of Ten Days + Another World, a different Naruto, not a brainless article)
Itachi Uchiha, rebel, genocide, terminator.
When he opened his eyes, he was reborn and returned to three years before the genocide was exterminated.
He opened the [Eye of Finality], and every time he "abandoned it", he obtained a Seal of Finality:
➤ Abandon gentleness and awaken [Tsukiyomi · Fantasy God Realm];
➤ Give up hope and control [Amaterasu·Eternal Black Flame];
➤ Abandon family ties and activate [Susanoh·God of Disintegration];
The more he gives up, the stronger he becomes.
But if he doesn't give it up, he's not even a "person" anymore.
Until that day, my younger brother Sasuke yelled: "Are you still my brother?"
He smiled.
"I am no longer your brother... But I will still kill everyone in the world for you."
