Shoma transforms into Kamen Rider Gavv. He loves sweets and works at HapiPare. He is the youngest son of the Stomach family. The Stomach Company calls him Red Gavv. He is a half-human, half-Granute.

Hanto Karakida transforms into Kamen Rider Valen. A freelance writer who was modified by Kenzo Suga to be able to transform into Kamen Rider Valen.

Lakia Amarga transforms into Kamen Rider Vram. He likes stones and his catchphrase is "What a drag." In the Granute world, he used a fake name and spent time as Lage 9. He has a deceased younger brother.

Kenzo Suga transforms into Kamen Rider Bake. The researcher who modified Hanto Karakida and developed Bitter Gavv.

Dark Shoma transforms into Kamen Rider Bitter Gavv. A being created by Kenzo Suga.

A researcher who developed Vram's belt. The older brother of Shoma and Jeeb, and the second son of the Stomach family.

The president of HapiPare and a gyaru. She calls Gavv "Umasho," Valen "Hanty," and Vram "Lakian."

The older brother of Nielv, Shoma, and Jeeb. He is the president of the Stomach Company, a dark candy business. He has an asymmetrical wolf cut with red point mesh. The eldest son of the Stomach family.

The younger brother of Lango and Nielv, and the older brother of Shoma. He transforms into Kamen Rider Bitter Gavv Bakibaki Stick. He has no connection to the other Dark Shoma Bitter Gavvs. He is the husband of Glace Jardack and is kind to her. The third son of the Stomach family.

Jeeb's wife. A curious only daughter of a wealthy family. She wears a blue dress and carries a silver-haired blue umbrella.