Shiba

is a ninken, and personal summon of Kakashi Hatake.

Background
In the anime, after they made a contract with Kakashi, Shiba and the other ninken aided him to search the abducted Rin Nohara by the Kirigakure shinobi and acted as a diversion in order to allow them to flee. They also helped searching for the fleeing Orochimaru.

Appearance
He has light grey fur with a white underside and a black crest on his head reminiscent of a mohawk. His eyes are round and have dark markings above them, not unlike those of Kisame Hoshigaki. He also wears the standard outfit of Kakashi's ninken which consists of a blue vest with the heno-heno-moheji seal and a Konoha forehead protector around his neck and bandages on his front legs.

Abilities
Shiba possesses heightened senses with which he can use to track his target with ease. He has also demonstrated the ability to track his target underground through the use of the Summoning: Earth Release: Tracking Fang Technique as well as hold a target down, allowing Kakashi to attack them freely. He also has exceptional teamwork with the rest of his pack, able to develop and effectively use several offensive and defensive formations in battle which make use of the manoeuvrability and powerful limbs.

Prologue — Land of Waves
Kakashi called on Shiba and the ninken pack to track and capture the missing-nin Zabuza Momochi. They managed to bite onto the missing-nin and pin him in place. This allowed Kakashi to use Lightning Cutter without fear of a counter attack.

Sasuke Recovery Mission
Shiba and his fellow ninken were summoned by Kakashi to track down Naruto Uzumaki and his team who had gone off in pursuit of Sasuke Uchiha.

Sunagakure Support Mission
In the anime, Shiba along with the other ninken, were summoned by Kakashi to investigate the Takumi Village.

Kazekage Rescue Mission
At the start of Part II, Shiba and the ninken pack were called upon to track down the Akatsuki member Sasori using a small piece of his clothing.

Itachi Pursuit Mission
Kakashi summoned the pack to help track down Itachi Uchiha. He and Bisuke were partnered with Sakura.

Five Kage Summit
In the anime, Shiba was seen along with Akino, Urushi, Bisuke and Ūhei being deployed by Kakashi each carrying scrolls with intel for the other hidden villages.

Kakashi Hiden: Lightning in the Icy Sky
Kakashi summons Shiba and the other ninken to search for the exploding tags planted around the Tobishachimaru. Once they gather all the tags, the ninken give them to Might Guy.

Konoha Shinden: Steam Ninja Scrolls
In the manga, Kakashi sent Shiba to track Mirai Sarutobi, who had left their inn in the middle of the night, leading Kakashi and Guy to the lair of the Jashin cult.

Trivia

 * The is a breed of small dogs found in Japan. "Shiba" alone stands for various things like "lawn" (芝) or "firewood" (柴).
 * His fur was coloured red in Part I, but was later changed to silver in Part II.