Griffon Katou, often called Griff for short, is a small, unusual blue creature who serves as the navigator and cartographer for the Rave Warriors. His body is malleable and blob-like, resembling a blue mass with a long, dangling nose, large red lips, and a skirt-like feature at his base that gives him a distinct appearance. He stands approximately eighteen inches tall, possesses no legs, and has arms that are long enough to reach the ground. A notable oddity about Griffon is that he floats in the air while sleeping, a phenomenon with no clear explanation within the series. He is often seen riding a strange, purple, horse-like creature named Tanchimo, whose head is in constant, rapid motion.

Griffon's background reveals that he is a sentenoid who lived on a small island that was embroiled in a war with a group called the Pudding Head army. Before joining the main cast, he served as a horse and carriage chief. His path crosses with the main characters when he is hired to escort Haru Glory, Elie, and Plue to their next destination.

The character's personality is defined by a striking contrast between his perverse tendencies and his genuine loyalty. On one hand, Griffon is a self-admitted voyeur and a pervert. He is frequently seen attempting to spy on Elie, particularly while she is bathing or changing clothes, and has even stolen her undergarments on multiple occasions. He has also been known to take inappropriate photographs of women. On the other hand, he demonstrates a deep and sincere care for his companions, especially Elie. This is most clearly shown during the Symphonia Arc, when he does not hesitate to jump in front of a sword meant for her, an act that results in his own body being cut in half. His primary motivation stems from his past, as he holds the creature Plue in the highest regard. After Plue was mistakenly believed to have sacrificed himself to save Griffon's island, the islanders began calling him Master Plue, and Griffon has continued to praise and follow him devotedly ever since.

In the group, Griffon's primary roles are those of a cartographer and navigator, using his skills to guide the Rave Warriors through their complex journey. He has little to no skill in direct combat and is not a fighter. To compensate, he makes use of his limited shapeshifting abilities. He can stretch his limbs, inflate parts of his body, or compress himself to fit through small gaps. While generally not useful for fighting, this malleability allows him to perform utilitarian tasks, such as transforming into a makeshift roof to protect Haru and Elie from the rain. A unique and somewhat disturbing ability he possesses is the power to survive being split in half. When this occurs, the two halves can live independently as Griffon Ka and Griffon To; however, he will die if the two halves are not rejoined within six and a half hours. His most significant relationship is with Plue, whom he follows with extreme reverence, and he shares a complex bond with Elie, vacillating between obsessive peeping and genuine protective instincts. Throughout the story, Griffon remains a consistent, albeit quirky, member of the team, providing navigation, comic relief, and surprising moments of courage that demonstrate his growth from a simple perverted creature into a true, if unorthodox, companion.