C

is a jōnin from Kumogakure.

Background
In the anime, when Konohagakure and Sunagakure sent an invitation for Kumagakure to join in an impromptu Chūnin Exams, the Fourth Raikage scoffed at the idea, believing it to be a joined attempt from the two villages to attack Kumogakure while its defences were lowered. A rejected the offer and sent C and Darui to make sure Killer B would not sneak off to this event.

Personality
In contrast to his easy-going partner, C is portrayed as a very serious and mature individual normally seen with a look of self-assured as well as confident look on his face. He often puts duty above all else, as shown when he told Darui there was no time for rest upon their return from the Kage Summit as they had to begin planning immediately. He also seems to have a slight dislike for Konoha ninja, calling Naruto's group "Konoha dogs".

Appearance
C is a young man with short, blond hair and dark eyes. He wears a sleeveless black shirt with a one-strap-over-one-shoulder white flak jacket, black forehead protector, characteristic black, elbow-length arm-guards, and the red and white Kumogakure shin-guards along with a pair of sandals.

Abilities
C is a sensor-type shinobi, allowing him to sense the chakra of others even from extended distances. Additionally he is a medical-nin which gives him an even greater support role on the battlefield. He also appears to be very analytical, and knowledgeable on foreign shinobi techniques, as he is shown recognising Sasuke Uchiha's Mangekyō Sharingan, along with Amaterasu, even having knowledge on Itachi Uchiha's use as well. C was able to deduce how Sasuke's Fire Release worked after only seeing it once.

C is a skilled genjutsu user, witnessed from his use of the Lightning Release: Lightning Illusion Flash of Lightning Pillar technique which makes use of his Lightning Release nature transformation to emanate light from his entire body to blind his opponents. His genjutsu prowess is further exemplified by his placing a secondary genjutsu within the first.

All of these abilities also imply a mastery of multiple skills requiring very fine chakra control. Also of note is when he went to defend the Raikage from the bodyguards of the other Kage he took a defensive, taijutsu stance, implying that he is competent in close-range combat as well.

Five Kage Summit
C and Darui were chosen to escort the Fourth Raikage to the Kage Summit in the Land of Iron. During a brief rendezvous with Team Samui while en route, C sensed that they have been followed by Naruto Uzumaki, Kakashi Hatake, and Yamato and after the Raikage spoke with the Konoha-nin, they continued on their way. Once they arrived and the meeting began, C and Darui came to the Raikage's defence following his outburst, blocking the attacks of the other Kage's bodyguards. After being told to stand down, they returned to their posts after things settled down, only to again come to the Raikage's side when White Zetsu appeared. White Zetsu revealed that Sasuke Uchiha, Killer B's captor, was nearby, so C and Darui accompanied the Raikage in tracking Sasuke down.

C located Sasuke and his team and reported a number of samurai casualties as they got nearer. When they arrived, C launched an attack with his Lightning Release: Lightning Illusion Flash of Lightning Pillar technique to blind Sasuke and his team, creating an opening for the Raikage and Darui to attack. The Raikage then instructed C to find and eliminate Sasuke's sensor. C was not able to defend himself properly during his search, and despite Darui's attempts to keep him safe, he is struck by one of Sasuke's genjutsu and passed out. Darui later revived him and helped him get on his feet, and together they observed the Raikage's fight with Sasuke. The Raikage was eventually struck by Sasuke's Amaterasu and was forced to cut off his arm. When the fight was interrupted by the Sand Siblings, C used medical ninjutsu and stopped the bleeding and silently worried about how far the Raikage was willing to go.

While the Raikage was being healed, Sasuke escaped. They followed him to the Summit hall, where Tobi explained his Eye of the Moon Plan to them. As part of his explanation he revealed that B only pretended to be captured; C sighs at this most recent example of B trying to get some vacation-time, which did not surprise Darui. After the formation of the Allied Shinobi Forces, C joined the Raikage in searching for B. Before they leave, C told the samurai that two members of Sasuke's team were still in the area.

From several miles away, C was able to detect B's chakra contained within a large sphere of water. When they arrived there, they found B fighting Kisame Hoshigaki. C thanked Kisame for producing the water dome and thus, inadvertently helping them find B. After Kisame was "eliminated" they all returned to Kumogakure. C later attended a war council meeting where he advised the Raikage on how to form a reconnaissance team to find the Akatsuki base.

Fourth Shinobi World War: Confrontation
When the war began, C was placed in the Sensor Division. C was a bit unsettled since it is the first war he would ever fight in. However, Ao told him that if they did their jobs well, they could have a huge impact on the outcome of the war and not to slack off.

Fourth Shinobi World War: Climax
On the second day, mobilising with the remaining members of his division and the Allied Shinobi Forces, C arrived at the battlefield where the jinchūriki were. With this, he and the other members of the Allied Shinobi Forces stood to face their opposition. Following the strategy relayed to them by Shikaku, C and Darui, along with several other Kumo-nin begin the assault. Launching their assault, C and several others blinded the enemy with the Lightning Release: Lightning Illusion Flash of Lightning Pillar technique, allowing Darui and other Storm Release bearers to use the Storm Release: Laser Circus technique to aim for the beast's eye.

Birth of the Ten-Tails' Jinchūriki
Following Obito Uchiha's attack of the shinobi on the battlefield, it was revealed that C, while sustaining injuries, was still alive. He later commented on the change that had occurred in Naruto Uzumaki's chakra from a sensory perspective and when he recovered, he fought alongside the other members of the Alliance while shrouded in Kurama's chakra. Later, as the Alliance succeeded in freeing the tailed beasts from Obito, C sensed that the latter was still alive and immediately notified his comrades. As C notices the tailed beasts were about to face Madara, he orders the alliance to move away from the area.

Creation and Conception
Masashi Kishimoto noted that he created C with a cool, good-looking male idol in mind, but also as a serious character. As such, C generally has a look of aplomb on his face and wears the standard attire of Kumogakure without any embellishments.

Video Games
In Naruto Shippūden: Ultimate Ninja Storm Generations, Naruto Shippūden: Ultimate Ninja Storm 3 and Naruto Shippūden: Ultimate Ninja Storm Revolution,  C is a support-only character.

Trivia

 * "Shī" is the Japanese pronunciation of the letter "C". This parallels the name of several other shinobi of Kumogakure whose names are letters of the alphabet.
 * In Naruto: Shippūden episode 261, when deploying with the Sensor Division, C is not present like he was in the manga. He is instead replaced with someone else.