Shin

was a Konohagakure orphan who was recruited into the "Root" division of the ANBU.

Background
Even though he was trained to abandon his emotions, Shin grew close to a younger Root member, Sai. He recognised Sai's talent for art, and encouraged him to continue the hobby. Sai looked up to him as a brother and began to shed Root's teachings, but Shin soon died of an unknown disease, leaving Sai's training to suppress most of his memories of Shin. Prior to Shin's death, it was noted that he and Sai were supposed to fight to the death by Root regulations, in a final step to eradicate emotions. After Sai met Naruto Uzumaki, who he noted to be similar to Shin, Sai's memories of him returned, which brought a smile to his face.

Personality
According to Sai, Shin and Naruto are very similar. He commented that Shin was loud, impatient, and unrefined. Shin seemed to be a kind boy because he helped Sai pursue his interest in drawing. Sai looked up to him because Shin seemed to disregard his personality training in Root. It is known for sure that Sai regarded him as an older brother. He was also very tenacious and absent-minded.

Appearance
Shin had grey hair and black eyes. When he was a child, he wore a pale yellow shirt together with a pair of dark brown pants. These outfits were the ones he wore in the cover of Sai's picture book. When he was older, he wore official uniform of the ANBU, and carried giant shuriken as well as a tantō on his back. Unlike all other members of Root that wear a short jacket, he didn't.

When he was resurrected by Kabuto, he is seen in an outfit exactly like the one his brother wears inclusive of the Root jacket.

Abilities
Shin was a skilled shinobi during his lifetime, enough to be resurrected by Kabuto to fight in the Fourth Shinobi World War. When he fought against the Alliance's Surprise Attack Division, he used a tantō similar to Sai's and was shown to be very skilled at close range combat.

Shinobi World War Arc
Kabuto Yakushi summons Shin, using Summoning: Impure World Resurrection, as part of Akatsuki's line up for the Fourth Shinobi World War. Shin becomes a member of Akatsuki's Surprise Attack and Diversion Platoon, and his assigned role within the Platoon is to serve as Back-up and Support for the other members. When the Platoon first engages the Allied Shinobi Forces' Surprise Attack Division, Sai attacks Shin from above and manages to break Shin's neck.

However, since he has been resurrected, Shin regenerates immediately. He then tells Sai to run away. He springs forward, attacking Sai with his tantō. After Omoi cuts the chakra threads on the Konoha shinobi Sasori was controlling, he attached chakra threads to Shin instead, using him to combat Kankurō. Upon it being revealed that he has Deidara's explosive clay packed into his stomach.

Kankurō manages to capture him with the Salamander puppet, where he explodes. Due to being under the influence of the Summoning: Impure World Resurrection, he reformed. He told Sai that he didn't want to hurt him, as he is dead and had been freed from Root. As Sai attacks Deidara and Sasori in a rage, Shin sees the drawing Sai made of himself and Sai together, remembering when Sai first started to draw it. After Deidara and Sasori were captured, Sai said that they should finish the fight they never got to start. Shin, however, tells him there's no need, as finally seeing Sai's drawing freed his soul. Then he crumbled into ashes, leaving behind the corpse of an unknown person that was used as part of the ritual.

Quotes

 * (To Sai) "I finally saw the drawing I'd always wanted to see… It looks like your drawing has freed my soul."