Usako is a recurring rabbit student attending Mimi-sensei's elementary school in the Anpanman franchise, consistently portrayed alongside classmates Pyonkichi and Usao. She wears pink clothing. Debuting in the series' second episode, Usako and her rabbit friends encountered Anpanman in a tree. Demonstrating resourcefulness, the trio later constructed a tricycle from their unicycles to help Anpanman return to the bakery. Her narrative often involves school activities and interactions with the broader cast, including perilous encounters such as Baikinman attempting to force-feed her spaghetti laced with poison mushrooms. Usako has a pet poodle named Rare Cheese, introduced nearly eight years after the anime began. Rare Cheese became Cheese's love interest. Their first meeting occurred while Usako and Rare Cheese were picking flowers with Melonpanna and Cheese. When Baikinman captured Usako and tried to steal the flowers, Rare Cheese collaborated with Cheese to mount a rescue. Cheese confronted Baikinman directly while Rare Cheese sought Anpanman's help. After Anpanman freed Usako, Rare Cheese notably rescued Cheese from a waterfall. Rare Cheese exhibits tertiary sexual characteristics like eyelashes and a hair bow, with her fur sometimes depicted with a pink tint across various media. Usako appears in group settings with other child characters during educational segments and lighter narratives. She was promoted to the series' opening titles sequence starting from the fourth opening theme. The character shares her name with a figure in the NHK Asadora drama "Anpan," an unrelated entity.