C

is a jōnin-level ninja of Kumogakure, who currently functions as a bodyguard, escort and medic to the Fourth Raikage at the Kage summit, along with his fellow jōnin Darui.

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 of a Kumogakure jōnin over it. He wears black elbow length arm guards, and red and white Kumogakure shin-guards.

Personality
In contrast to his easy-going partner, C is portrayed as serious and putting Kumo's well being above all else. This is briefly shown when he told Darui there was no time for rest upon their return from the Kage Summit. He also seems to have a slight dislike of Konoha ninja, calling Naruto's group "Konoha Dogs".

Abilities
C is a sensor type shinobi, allowing him to sense the chakra of others even from extended distances. He is also a medic-nin and seems to be very knowledgeable on foreign shinobi techniques, as he is shown recognizing Sasuke's Mangekyō Sharingan along with Amaterasu. C was able to deduce how Sasuke's Blaze Release worked after only seeing it once. He is also a skilled genjutsu user, as he was shown using Lightning Illusion Flash of Lightning Pillar, followed by a second 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 defense taijutsu stance, implying he is capable of close combat as well.

Five Kage Summit Arc
He and Darui were called to escort the Fourth Raikage to the Five Kage Summit in the Land of Iron. When the Raikage jumped through a window, C suggested to Darui that they follow him, but Darui said that he would use the door. After that, he was shown to be the one who noticed that Team Samui had been followed.

During the Kage meeting, he quickly jumped to protect the Raikage after he smashed the table, because the bodyguards of the other Kage entered into defensive position. After the other bodyguards returned to their respective place, C and Darui did the same. When White Zetsu appeared during the Five Kage Summit, C along with Darui guarded the Raikage and followed him to the battle with Sasuke Uchiha. Due to his chakra sensing skills Sasuke, Jūgo, and Suigetsu decided that in order for Karin to find Danzō without being detected they have to kill him, causing Jūgo to go into his level 2 cursed seal state. While the Raikage and Jūgo did battle, C acted as an observer commenting on their abilities. When Jūgo released a huge blast, C worried over the Raikage's well-being before being trapped in a genjutsu by Sasuke and passing out.

He later woke up with Darui beside him, after the Raikage used the technique Liger Bomb. Actually, he was unable to move because of Sasuke's illusion and Darui supported him. C, later, recognized the Mangekyō Sharingan on Sasuke's eyes. Then, Sasuke used the Amaterasu and unleashed it on the Raikage, amazing C with his control of the black flames. He knew about the Amaterasu technique and observed that Sasuke could control the flames and change their shape, later he suggested that Sasuke is even more skilled than Itachi. C showed up to be worried about the Raikage, when he gave up his left arm.

Sasuke counters, and the Raikage is saved from futher harm by Gaara. As Gaara talks to Sasuke, the Raikage makes his way to C, chops the arm which was being burned by Amaterasu, from the elbow down, and asks C to stop the bleeding with his medical ninjutsu. After Sasuke destroys the ceiling's foundations with Susanoo, C is protected by the Raikage. Afterward, he, along with Darui, follow the Raikage to track down Sasuke.

Upon returning to the meeting hall, C finds that Madara Uchiha has rescued Sasuke and Karin and teleported them out of danger. Madara then proceeds to tell them about his Eye of the Moon Plan to rule the world by unlocking the Ten-Tailed Beast and casting an Infinite Tsukuyomi. When Madara asks them to hand over the Eight-Tailed Giant Ox and Nine-Tailed Demon Fox, and notes that Killer Bee has escaped, C sighs in annoyance at Killer Bee's ploy of getting a vacation.

After Madara's declaration of the Fourth Great Shinobi World War and subsequent departure, the Raikage assigned C to locate Killer Bee, and bring some shinobi from the village to form the search party. Once they find Killer Bee and Kisame, C thanks Kisame for his use of the water sphere, because he could sense the Eight-Tails' chakra in the sphere from miles away. After the Raikage and Bee decapitated "Kisame", C watches on the sidelines as the two brothers bicker.

Confining the Jinchūriki Arc
When they returned to Kumogakure, Darui wanted to take a breather despite the Fourth Raikage's Assistant asking for a quick briefing of the situation. C contrasted Darui's desire to rest by indicating that things are getting more important than when Bee went missing. Later at the war meeting with his fellow ninja he reccomended to the Raikage to form reconnaissance teams since they had not located the enemies base. He then proceeds to tell the Raikage how to position them.

Trivia

 * Shī is the Japanese pronunciation of the letter "C". This parallels J's name, which is the pronunciation of the letter "J", and Killer Bee's name, as "bī", the Japanese pronunciation of "bee", is also the Japanese pronunciation of the letter "B". The same applies to the Fourth Raikage's name, A.