Haroshi is a small, energetic flying squirrel who serves as the best friend and constant companion to Hello Kitty in the animated series. This little creature lives together with Kitty and is almost always seen scurrying or gliding alongside her during her daily activities in their hometown of Cherry Town. Haroshi has a sand-tan colored coat with white accents on his face and belly, complemented by pale flesh-colored paws and a small nose. His black whiskers and dark eyes give him an expressive appearance, and the wing-like excess skin between his limbs allows him to glide gracefully through the air.

The personality of Haroshi is marked by an abundance of energy and a deep sense of curiosity, which makes him an ideal partner for adventure. He possesses a strong sense of justice and becomes visibly upset when someone behaves unfairly or incorrectly, often voicing his displeasure through a series of agitated squeaks. Despite his very small size, Haroshi has a big personality and is not shy about making his feelings known. He becomes especially vocal when he feels he is being ignored or when something is amiss. Haroshi also has a notable love for food, with a particular soft spot for smoothies, and he takes pleasure in keeping his surroundings neat and tidy.

In his role within the story, Haroshi is content to let Kitty take the lead during their adventures, but he is far from a passive observer. He frequently plays a crucial role from the sidelines, using his keen attention to detail to notice small but important things that other characters have overlooked. On several occasions, this unique ability allows him to save the day by providing the missing piece of a puzzle or pointing out a hidden clue at just the right moment. His curiosity ensures he remains actively involved, always ready to help put Kitty's plans into action. One of his most distinctive traits is his method of communication. Haroshi does not speak in a conventional human language; instead, his vocabulary primarily consists of the exclamation Badoo, along with various chirps, chittering sounds, and squeaks. Despite this limitation, he is able to convey his thoughts and emotions effectively, whether he is happily chirping for a hug, expressing excitement over collecting colorful pebbles, or protesting against an injustice.

The relationship between Haroshi and Hello Kitty is the central bond of his character. He is her loyal sidekick and best friend, and Kitty loves him precisely for his strong-willed and expressive nature. He is always willing to assist her, and the two work together as a seamless team to solve the problems of the townspeople. Beyond his friendship with Kitty, he interacts with the wider cast of Cherry Town, including characters like the energetic Frido and the inventive Zonty. As the series progresses, Haroshi remains a steadfast source of support for Kitty. His courage and willingness to help, despite his small stature, are consistently demonstrated, and his ability to glide proves useful in many situations. He is sometimes referred to as living with Kitty, suggesting a household companion dynamic. In essence, Haroshi is a loyal, curious, and food-loving flying squirrel whose sharp eyes and big heart make him an invaluable friend and a surprisingly effective hero in the adventures of Cherry Town.