Gamakichi

is a toad from Mount Myōboku.

Personality
He is rather funny, and has the mannerisms of a smart-aleck. He is also often very condescending as well as light-hearted in most situations, preferring the levity of talk to the seriousness of battle. He seems to favour Naruto because he saved him from Gaara in his miniature Shukaku form. After he is summoned he tends to greet people by saying, "Yo" (in English dub, "Hey").

Appearance
Gamakichi debut as a young orange toad with purple markings around his eyes, mouth and stomach. In Part I, he was small enough to fit on top of Naruto's head like Akamaru could fit on top of Kiba's head and wore a blue jacket. After the time-skip, Gamakichi has grown much bigger in size, though not nearly as big as his father, Gamabunta, but now Naruto can ride on his head and he can carry an adult human in the palm of his hands. He still sports a blue jacket.

In Part II, Gamakichi has not just grown in size but in maturity as well. Gamakichi seems to have a considerably large amount of knowledge when it comes to human-toad combination techniques and nature energy. Also, he seems to be on better terms with his younger brother, Gamatatsu, as shown by him no longer calling him an idiot.

Abilities
Though his abilities have not been expounded on much in the manga, in the anime, Gamakichi has a shown a variety of techniques. He has been shown to be able to shrink his body size for infiltration purposes. In the manga he's shown the ability to use the Reverse Summoning Technique and summon Naruto from wherever he is.

Nature Transformation
In the anime, Gamakichi has shown the ability to use fire-release techniques, which includes the Fire Release: Flame Bullet and the collaboration technique with his brother and Naruto called the Wind Release: Toad Oil Flame Bullet.

Invasion of Konoha Arc
During the fight with the transformed Gaara, Sakura was slowly being crushed, and Naruto decided it was time to summon Gamabunta. However, due to poor chakra control, he could only muster enough chakra to summon Gamakichi. Despite being irritated, Naruto kept Gamakichi safe from Gaara's attacks. When Naruto finally managed to summon Gamabunta, Gamakichi convinced his father to help in the fight, saying that Naruto needed help saving his "girlfriend".

Search for Tsunade Arc
Gamakichi is summoned by Jiraiya due to his inability at the time to control his chakra during his fight against Orochimaru. He would later tell his brother Gamatatsu to run away when their father, Katsuyu and Manda with their respective summoners are about to fight.

Land of the Rice Fields Arc
In the anime, Jiraiya summoned him again to check for traps at the entrance of Orochimaru's hideout.

Land of the Birds Arc
Gamakichi made a short appearance in the Land of Birds when he and Naruto needed Gamatatsu. Despite Naruto thinking he would be useless, Gamatatsu, using his curiosity, found a kite that was a clue about how the Cursed Warrior flew. Later, he went down a dark tunnel with Naruto and Gamatatsu, and was caught by the Daimyō and his guards.

Land of the Sea Arc
He was summoned again with Gamatatsu by Naruto in the Land of the Sea, although it was another attempt by Naruto to summon Gamabunta. Upon learning this he warned Naruto that it would be a big mistake to summon his father to the middle of the ocean, since toads are freshwater creatures.

Three-Tails Arc
Although he did not have his Part II debut until much later in the manga, Gamakichi appeared sooner in the anime adaptation. Noticeably, Gamakichi was not yet as big as he would be in his manga debut, by which time he would be big enough for Naruto to stand on his head. In his anime debut, Gamakichi was easily big enough for Naruto to stand on his back.

When Naruto proved incapable of synchronising with Gamariki to learn collaboration jutsu, Naruto decided to summon Gamakichi and Gamatatsu, as he had worked well with them before. After successfully synchronising with them, Naruto learned that neither of them had any skill in Water Release technique. With Naruto's help and lessons from their father, Gamakichi teaches the basics of Water Release to Gamatatsu.

Later, when Team Yamato found it impossible to break through Guren's crystal barrier via conventional means, Naruto summoned Gamakichi and Gamatatsu to help. Gamakichi kept Gamatatsu focused by warning him that he wouldn't get any snacks if he didn't focus on the task at hand. This enables Gamatatsu to break through the barrier, after which they return to Mount Myōboku. To their annoyance, however, Naruto keeps summoning them again, both to combat Team Guren and the Three-Tails. While fighting the latter, Gamakichi pointed out that their Water Release technique would be ineffective against its own water-based abilities. Naruto lamented the fact that they had no Fire Release technique at their disposal to evaporate the beast's water, but Gamakichi pointed out that he could use fire release and together with him using the Fire Release: Flame Bullet technique, they were able to perform the Wind Release: Toad Oil Flame Bullet.

After sending Gamatatsu back briefly to Mount Myōboku to bring back a stomachful of toad oil, Naruto, Gamatatsu, and Gamakichi combined their techniques to create the Wind Release: Toad Oil Flame Bullet. The resulting inferno drove through the Three-Tails' water attack and had the turtle demon fleeing under the lake's surface. Once the Three-Tails had been overcome, Gamakichi and Gamatatsu went back home.

Invasion of Pain Arc
Gamakichi made his Part II debut in the manga when Naruto was informed of Jiraiya's death. He appeared again during Naruto's senjutsu training, watching as he trained under Fukasaku. He was summoned again during Pain's attack on Konoha, where Naruto instructed him to get Tsunade to safety. He stays with Sakura, laughing when the Deva Path starts running away to use Chibaku Tensei, thinking Naruto has scared him off. Sakura reprimands him quickly after this, reminding him of the danger with Naruto. He is later seen with the other villagers congratulating Naruto on his success against Nagato.

Trivia

 * His name means "Propitious Toad".