Poomo serves as Princess Grace's loyal attendant before becoming the dedicated guardian of twin princesses Fine and Rein. He possesses white fur, purple eyes, large ears, a long tail tipped with an orb, pink cheeks, and a visible tuft of blond hair beneath his pointed blue hat. This hat features an orange sun symbol, a magenta jewel, and gold accents. He also wears a purple bow tie and two blue star-shaped earrings.

Initially presented as a pet to the princesses, Poomo utilizes "Telepoomotion" for interdimensional travel during their mission to save Wonder Planet. He handles practical tasks like cooking, sewing, and piloting, and consistently ends his speech with "de pumo".

Poomo exhibits a serious, kind, and deeply loyal personality, though he frequently shows exasperation towards Fine and Rein's early immaturity, often repeating instructions or rolling his eyes. He undertook personal training early on to become more reliable, inadvertently reuniting the twins during a self-induced predicament. His faith in their capabilities grew as they achieved unprecedented Princess levels.

His loyalty manifests in self-sacrifice, repeatedly placing himself in danger to protect the twins. He nearly died for them at the conclusion of the first season, expressing that both princesses brought him happiness, surviving only through intervention from the last Grace Stone and Princess Grace.

In the sequel series "Gyu!", Poomo's role diminishes as Fine and Rein gain new mascots, though he continues accompanying them. His relationship with the twins evolves from long-suffering tolerance to mutual trust and admiration, reflecting his recognition of their growth. He maintained unwavering devotion to Princess Grace until her death, extending the same commitment to her daughters.