Petit Charat, commonly known as Puchiko and sometimes listed under the alias Cappuccino, is one of the main characters of Di Gi Charat Nyo. She is a very young catgirl, described in some materials as a tiger girl, from the planet Di Gi Charat, and she is the younger sister of the character Di Gi Charat, usually called Dejiko. In Di Gi Charat Nyo, Puchiko travels to Earth together with Dejiko and the floating guardian Gema as part of princess training. During their arrival the group is accidentally separated, and Puchiko ends up living at the Ankorodo cake shop, a traditional Japanese confectionery run by Daifuku and Kinako Ankoro, while Dejiko stays at the Omocha brothers' toy shop. The two keep in contact through special communication devices called Mystery Phones. Within the larger franchise, Puchiko's bond with Dejiko is sometimes explained by an earlier incident in which Dejiko rescued her, with Puchiko following her out of gratitude, while other accounts describe the two as sharing the same parents. Di Gi Charat Nyo presents an alternate version of the story, and within this series she functions mainly as Dejiko's young companion and assistant.

In personality, Puchiko is notably quiet and stoic. She rarely speaks at length and usually ends her short sentences with the verbal tic "nyu." She tends to stay calm in situations where Dejiko and others panic, and she does not seek attention for herself. Despite her reserved manner, she has a sharp tongue when provoked, and she has an interest in the occult. Her affectionate and unassuming temperament contrasts with Dejiko's excitable, lazy behavior. In appearance, she is a small girl with long brown hair, brown eyes, cat ears, a tail, and small bells in her hair that are smaller than Dejiko's, and she typically wears a sailor-style uniform with a light blue or schoolgirl outfit and orange boots.

Her motivations in Di Gi Charat Nyo center on accompanying Dejiko through the princess training assignment and adapting to life on Earth. She is dutiful, gentle, and uncomplaining, settling into the household of the Ankoro couple and taking part in the daily life of the town. Her quiet loyalty to Dejiko is the clearest driving force behind her actions, whether she is helping with everyday tasks, following Dejiko's plans, or simply staying close to her older sister.

Within the story, Puchiko is a main presence throughout the series. Her role includes serving as a calm counterpart to Dejiko and connecting the group to the town through her stay at the cake shop. The Omocha brothers, especially Yasushi, are frequently portrayed as being strongly charmed by her, while Daifuku and Kinako Ankoro act as her caretakers. In the later part of the series, after a princess school is introduced in the second half of the run, the main characters, including Puchiko, attend classes there under the supervision of Dejiko's mother, who appears as the principal. A small cat named Hokke Mirin is also often shown at her side in the broader franchise.

In terms of abilities, Puchiko possesses a version of Dejiko's eye-beam power, but hers is still in training. She is usually too calm and gentle to produce the aggression needed to fire the beam properly, and her attempts often end in strange results, such as sludge or other objects coming out of her eyes instead of a working beam. Her catlike traits, including her ears, tail, and distinctive "nyu" speech habit, are among her most recognizable features.

Regarding development, Puchiko's arc in Di Gi Charat Nyo is understated. She begins as a quiet visitor unfamiliar with Earth and gradually becomes comfortable with her hosts and surroundings while remaining composed and loyal to Dejiko. Later franchise material set in an alternate future, such as the Winter Garden special, shows her as a teenager with a more mature and less sharp-tongued demeanor, reflecting a natural growth into a calmer and more responsible version of the same character.