Real name: Shoma Stomach. In the human world, he goes by Shoma Inoue. He transforms into Kamen Rider Gavv. Born to a human mother and a Granute father, he is a half-breed. He has a 'Gavv' on his stomach; when he eats sweets, cute little creatures called Gochizo embodying the power of the candy emerge from it. By setting a Gochizo into the Gavv and 'eating' it, he transforms into Gavv. Changing the Gochizo changes his form. Gochizo are single-use. He wears a brightly colored hoodie and long pants, with a zipper on the belly for his Gavv. His mother, his only blood relative among the Stomach siblings, was turned into Dark Confectionery. He works part-time at the 'Happipare' handyman service to make humans happy. He loves sweets. He speaks casually to Hanto and others, but uses polite speech with everyone else. He has a gentle personality.

Real name: Hanto Karakida. After his mother was kidnapped by a Granute, he was taken in by a freelance writer whom he calls 'Master.' However, his Master was also taken by a Granute, fueling his hatred for them. He underwent surgery by Suga, a self-proclaimed Granute researcher, gaining the power to transform into Valen. After various events, he now fights alongside Shoma. He trusts Shoma through their connection at Happipare. Chronologically, he knows Shoma is a Granute. He wears a long coat over what looks like an aloha shirt. He dislikes sweets.

Real name: Lakia Amalga. To uncover the truth behind the death of his younger brother, Comel Amalga, he infiltrates the human world as a Stomach Corp henchman. He acts like a top-tier worker to get close to the executives. He receives the Vrastam Gear and Doppling Gochizo from Nielb, gaining the power to transform into Kamen Rider Vram. Through fighting, he learns that Grotta killed his brother and vows revenge, joining forces with Shoma and the others. He eventually ends up working part-time at Happipare. He enjoys eating veined stones. His catchphrase is 'What a pain...'