Kabu serves as the magical assistant dispatched from the Magic Kingdom by the protagonist's father to retrieve her from Earth. He first appears as a crow, then permanently assumes the disguise of a five-year-old boy, posing as her younger brother to blend into human society.

Consistently characterized by mischievous behavior, Kabu delights in instigating pranks on the protagonist and her friends, frequently causing unpredictable chaos. This core trait defines his role across both the original 1966-1968 series and the 1989-1991 sequel, positioning him alongside characters like the Hanamura triplets and the witch Poron as a recurring source of comic disruption.

In the sequel series, he continues accompanying the protagonist back to the human world, now joined by Poron and Dabdab, a cat from the Magic Kingdom. This trio of magical children generates humorous turmoil through their combined antics. A notable instance involves Kabu collaborating with Poron and the Hanamura triplets to misuse the stolen staff of the Great Magical King (Daimaō) for mischief on Earth.

His documented traits—shape-shifting ability, familial disguise, and mischief-making—remain consistent throughout both television series and the 1990 film, with his background solely defined as a magical servant originating from the Magic Kingdom.