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. The anime expands upon Shin's death; Sai and Shin were forced to fight to the death by Danzō to fully kill their emotions. Knowing he is to succumb of his illness, Shin tells Sai to report to Danzō that he killed him in battle and that Sai must suppress his feelings. As Sai leaves to report to Danzō, Shin dies.

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 the 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 reincarnated 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 reincarnated 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
In preparation for the Fourth Shinobi World War, Shin is reincarnated by Kabuto Yakushi to fight against the Allied Shinobi Forces, before being assigned to the Surprise Attack and Diversion Platoon as the group's support.

After pursuing the three remaining members of the Infiltration and Reconnaissance Party atop Deidara's clay bird, he remains vigilant whilst Sasori manipulates the captive and booby-trapped Muta Aburame to attack the opposing Surprise Attack Division. Detecting that the enemy had evaded the blast, Shin tries to dive down to their position with tantō in hand, but is instead violently driven into the ground when Sai ambushes him from above. As his broken neck regenerates, he implores his "brother" to flee, remarking that they had no chance of victory. Briefly engaging Sai, Shin obstructs the enemy, after Omoi liberates Tokuma and Ranka. Confronted by Kankurō's Scorpion and Omoi, he avoids their attacks thanks to Sasori's assistance, when Hoheto reveals that his stomach was packed with explosives.

Just as he was about to detonate, Shin was captured by Kankurō's puppet, restricting the blast. However, due to the manner of his revival, he soon reformed. He then told Sai that he didn't want to hurt him, as he had already been freed from Root. As an enraged Sai attacks the others, Shin sees the image the former had drawn of the two together, recollecting the time when it was created. After the remainder of the platoon were restrained, Sai suggests they finish the fight they never got to start but Shin tells him there was no need, as finally seeing Sai's drawing had freed his soul. He then crumbled into ashes, leaving behind a pile of earth and the corpse of an unknown individual that were used as part of the ritual.

Quotes

 * (To Sai) "I… don't want to harm you. In death… I was finally free of "Root"."
 * (To Sai) "I finally saw the drawing I'd always wanted to see… It looks like your drawing has freed my soul."