Petit Charat, commonly known as Puchiko, is a young catgirl who appears throughout the Di Gi Charat franchise as the constant companion of the title character Di Gi Charat, or Dejiko. Her alternate name is Capuccino, and she is generally presented as Dejiko's younger sister or half-sister, although the original anime series does not explicitly explain their relationship. In the theatrical film, the character Gema identifies her as a princess, and in the prequel series Panyo Panyo Di Gi Charat she is shown living with Dejiko in a castle on their home planet. Background material from the Di Gi Charat Complete book states that Dejiko once rescued her by pulling her out of a hole, and Puchiko began following her out of gratitude. The Winter Garden special instead establishes the two as sisters who share the same parents. At the start of the original series she is described as being about five years old, making her noticeably younger than Dejiko.

In appearance, Puchiko is a small girl with long brown hair, brown eyes, cat ears, and a tail. She typically wears a sailor-style school uniform with blue bloomers, small cat-shaped bells in her hair that are smaller than Dejiko's, and orange boots, though some entries in the franchise depict her in a light blue dress. Her most distinctive speech habit is ending her sentences with the syllable nyu, which mirrors Dejiko's nyo.

Her personality is quiet, calm, and stoic. She speaks rarely, but when she does she can display an unexpectedly sharp tongue, and official profiles describe her as easygoing and occasionally sharp-witted. She tends to keep her composure in situations where Dejiko and others panic, and her reserved, laid-back temperament contrasts strongly with Dejiko's loud, impulsive, and self-centered behavior. This contrast makes her a natural foil: where Dejiko charges ahead with grand schemes, Puchiko observes quietly and often provides deadpan commentary or unexpected bluntness.

Her primary motivation is to stay with Dejiko, whom she follows out of loyalty and gratitude after being rescued. In the prequel series she shares a desire to leave castle life and help the people of her home planet find happiness, but in most versions of the story her role is simpler: she accompanies Dejiko on her adventures, supports her ambitions, and shares in whatever trouble the group stirs up. On Earth, she works alongside Dejiko at the Gamers store, taking part in the everyday retail misadventures that make up much of the original series.

Within the story, Puchiko serves as Dejiko's sidekick and younger-sister figure rather than the main driving force. She is a steady presence among the main cast, frequently seen with Dejiko and the guardian character Gema, and she also appears with the cat Hokke Mirin. Her relationships are centered on this small circle: her bond with Dejiko is the most important, while Gema acts as a guardian figure to both girls. She also interacts with the store's other worker, Hikaru Usada, and one recurring character, the wealthy Takurou Kimura, is particularly taken with her quiet charm.

Her most notable ability is an attempted eye-beam similar to Dejiko's, but she is usually too docile to summon the aggression needed to make it work properly. When she tries, the technique often misfires, causing unexpected substances to come out of her eyes, such as sludge. In later official profiles she is described as still practicing the eye beam, making her effort to master it a running trait.

Over the course of the franchise, her background is gradually fleshed out across different series and specials, shifting from an unexplained sidekick to a princess and finally to an acknowledged sister of Dejiko, while her core traits remain consistent: a small, soft-spoken catgirl who ends her sentences with nyu, keeps her cool under chaos, supports her sister figure with quiet loyalty, and provides a calm counterweight to the exuberant world around her.