Ganta, originally known as Junk in the early anime, is a friend of the protagonist Keroppi and a resident of Donut Pond. He has a birthday on October 10. Ganta is recognized as the strongest and most powerful frog in his community, often taking on the role of a leader or a big brother figure among his peers. However, his tough exterior contrasts sharply with a personality that is genuinely afraid of the dark and of heights; he is also notably fearful of snakes. Consequently, Ganta is careful about disguising these fears, presenting a brave front to the world while managing his internal anxieties. His special and somewhat unusual talent is the ability to turn himself into a rock, a skill he has used on various occasions.

Within the story, Ganta plays the role of a dependable, if occasionally struggling, friend. In the specific context of the anime Kero Kero Keroppi no Christmas Eve no Okurimono, Ganta is actively involved in helping his friends. In one story from that narrative, he takes initiative by bringing a generator, belonging to his friend Kyorosuke's father, in an attempt to restore the power of a character named Twinkle. Despite his good intentions, the plan goes awry when he sets the generator too high, resulting in him being electrocuted and causing some decorations to fall from a tree. Beyond this event, his role in Donut Pond is multifaceted. He has acted as a baseball coach for the Keroppies, although an initial poor practice caused him to quit before he later returned to the field. He also proves to be an active participant in adventures, such as when he gets lost in time with Keroppi and others, during which he meets a young frog named Nelson, stays at his house, and later helps build a treehouse for other friends.

Ganta’s key relationships are centered around his group of friends, including Keroppi, Keroleen, Kyorosuke, and Noberun, with whom he shares most of his adventures. A particularly significant relationship is with his father, Nelson. Through a time-travel adventure, Ganta meets Nelson as a child, and they build a secret house together, highlighting a strong familial bond. His character also shows development in overcoming personal fears. For instance, he initially reacts with terror upon meeting a purple snake named Choro, turning himself into a rock out of fear. However, he works past this instinct and eventually becomes friends with the snake, demonstrating his capacity for growth and change. Ganta also mentions having a sister, whose old mitt he once offered to bring for a baseball game. As for his notable abilities, aside from his great physical strength and the unique power of rock transformation, he also possesses a talent for building, as seen when he constructs a secret house and a treehouse for his friends.