It was Obito Uchiha

When Naruto extends a hand toward Obito, the offer is met with hostility as Obito clamps down on his throat and declares he regrets nothing he has done. Naruto knocks him back, telling him he has no right to call himself worthy of the Hokage title. The confrontation stirs something in Obito, who starts to glimpse traces of his younger self reflected in the boy. Naruto drives the point home, reminding him that Rin had longed for the Obito Uchiha of old, not the ruined figure he chose to become.

Memories of his days alongside Team Minato come flooding back as Obito wrestles with his own despair. Naruto seizes his hand and warns him never to dismiss the combined strength of everyone fighting. Back in the physical world, the shinobi succeed in drawing the tailed beasts out of him. Their armoured chakra cloaks fading now that the inner battle is won, Naruto and Sasuke bring Obito down at last. Defeated, Obito gazes up at the moon and mourns that he never managed to mend the emptiness inside him.

Obito rejects Naruto's outstretched hand and tries to strangle him. Naruto strikes back and challenges his claim to the Hokage title. Invoking Rin's wishes and Obito's memories of Team Minato, Naruto reaches him at last. In the real world the allied forces extract the tailed beasts, and Naruto and Sasuke finally defeat Obito, who laments the void left in his heart.

Chapter 654 was collected in Volume 68 within the Birth of the Ten-Tails' Jinchuriki arc and first appeared in Japan on November 25, 2013. Viz published it as I'm Uchiha Obito.