Akamaru

At some point, while Kiba was still in the Academy, his mother, Tsume Inuzuka, entrusted him with Akamaru. Although Akamaru almost immediately urinated on Kiba's face, much to his mother and sister's amusement, the two would soon become inseparable.

Akamaru has been described as active and devoted. This can be seen from his interactions with people, especially his best friend and companion Kiba whom he has always been with since the two met. They often spend their time going on walks, or more accurately, running through trees chasing one another. His devotion is most often seen when Kiba is hurt in battle; Akamaru will immediately run to his side. Rai no Sho, a story from Akamaru's point of view, reveals much of his personality. Akamaru is revealed to have a humorous thought process by erroneously explaining something, but then immediately correcting himself. He has a very scientific thought process about humans, thinking they enter oestrous too late in life when they should be focusing on being shinobi instead of finding a "mate". It's also revealed Akamaru is very overprotective of Kiba as he immediately tried fruitlessly to pull his master away from Tamaki when he realised the two had a strong mutual attraction to each other, as he didn't want Kiba to shy away from his training in favour of romancing Tamaki like "the others". In the epilogue, Akamaru had grown old and took delight in just napping most of the day and playing with his offspring. When prompted by Kiba to back him up, he mocked Kiba's notion that he turned down the Seventh Hokage seat, giving a sly smirk.

In Part II, Akamaru has grown into a full-sized adult large-breed dog. His size is such that Akamaru can now have Kiba ride on his back comfortably. Despite this, Kiba claimed he failed to notice due to the amount of time they spend together. Apart from his size, his general appearance has remained the same. Years after the Fourth Great Shinobi War, Akamaru aged a bit, with a few wrinkles appearing on his snout, though was otherwise unchanged. Akamaru's eyes are usually squinted, appearing closed, and he has a brown nose, as well as brown patches on his ears and a brown outline around his mouth. His fur on top of his head is styled to somewhat resemble a mohawk.

Akamaru's heightened senses, such as smell and hearing, along with Kiba's ability to communicate with him, makes him a highly capable ally for gathering and sharing information. He can 'sense' chakra with his nose, which allows him to judge an enemy's strength. In combat, Akamaru often takes Kiba's form (albeit having a much more feral appearance) using the Beast Human Clone technique. This gives him the ability to perform a ferocious spinning attack with the Passing Fang, which can be collaborated with his partner to make it more difficult for the opponent to avoid. The duo can also fuse together into a giant, two-headed wolf to perform a highly devastating attack. Due to the sheer speed of this attack, it is difficult for them to see their target. To make up for this, Akamaru would mark the target by urinating on them beforehand, allowing their heightened sense of smell to take over instead for attacks where they move to fast to see the target. He has also been shown to be adept at setting traps, such as explosive tags on his own. Akamaru has not been known to talk like some other ninken, but did speak briefly at the end of a special new years episode in the anime.