Rinna Charat hails from the planet Di Gi Charat and shares no biological relation with Dejiko or Puchiko. She first emerges as a main character in *Panyo Panyo Di Gi Charat*, established as a childhood friend to Dejiko, Puchiko, and Meek. Rinna consistently maintains polite manners towards others.

She runs a popular cake shop on her planet, celebrated for its delicious baked goods. However, the shop keeps irregular hours due to Rinna's frequent, unpredictable tendency to fall asleep suddenly at any time or place, often during daily activities or work. Despite this, Rinna possesses exceptional baking skills. Her approach emphasizes emotional care and anticipating customers' happiness as essential, metaphorically described as the "baking powder of the heart."

Rinna also demonstrates the physical ability to run at remarkably high speeds when needed, though she typically avoids it by preference. She eventually closes her shop temporarily to join Dejiko and friends on their adventures.

In *Digi Charat Nyo!*, Rinna appears as a minor character, retaining her core traits: cooking expertise, narcoleptic tendencies, Di Gi Charat origin without familial ties, and ending sentences with "-myu." Her later cameo in *Reiwa no Di Gi Charat* features characters acknowledging her return after a prolonged absence, reinforcing her narrative continuity.