When Obito returned to the hideout, he found White Zetsu corpses littering the floor, along with a severed arm Sasuke had left behind.
Tobi said, "Looks like the monkeys crowned themselves kings while the tiger was away~"
"Hmph." Obito bent down and picked up the severed arm. "At this point, it hardly matters. That fellow clansman of mine, the traitor, is a wolf pup whose appetite can never be satisfied. His leaving saves me some trouble. Besides, I no longer expect him to be able to handle Naruto."
Tobi asked, "Will your eyes be all right?"
Obito said gravely, "I'm afraid they won't hold out much longer..."
Tobi asked, "Then what will you do?"
Obito said, "I have a way. Let's go. There's no reason to stay at this hideout!"
Whoosh!
As the vortex spun, Obito arrived at a special place within his Spacetime dimension.
A cabinet stood there, its drawers holding some of the Sharingan recovered on the night of the Uchiha clan massacre!
Obito placed Sasuke's severed arm on a table and walked toward the cabinet.
"The scroll Madara left behind described a certain jutsu."
"It was created by Tobirama, the Second Hokage, and embodied a little-known ambition of his. That was why even Konoha's Scroll of Seals contained no record of its existence!"
"Using part of another person's body, you assimilate your own bloodline with theirs. Though it can't make them completely identical, it can make you like brothers!"
"Tobirama Senju's ultimate aim in developing this jutsu was to let the Senju obtain the Uchiha's power without transplanting Sharingan. Because it was too sinister, the First Hokage intervened and halted its development."
"The jutsu remains incomplete, so it can only be used within the same clan!"
"With this jutsu, though Sasuke and I belong to the same