Chisato Arashi, a third-year student at Yuigaoka Girls' High School and founding member of the school idol group Liella!, initially joined the music program focused on dance. She later transferred to the general program to dedicate herself fully to idol activities. Her athleticism and daily morning runs underpin her role as Liella!'s primary choreographer, committed to elevating the group's dance skills. She works part-time at a takoyaki food truck in Aoyama's Commune food court, driven by her fascination with round objects and enjoyment of cooking.

As Kanon Shibuya's childhood friend, Chisato initially hesitated to become a school idol, believing her place was supporting Kanon from afar. Before joining Liella!, she attempted to establish a dance club at Yuigaoka. A history of childhood bullying due to her meek demeanor, during which Kanon defended her, shaped her deep loyalty. She acknowledges others find her intimidating when angered, though this is rare. Sociable and attentive to school gossip, Chisato enjoys shopping with friends. She uses the informal greeting "Wissu wissu wissu!" and values sayings like "The early bird gets the worm."

Chisato overcame her reluctance to join the group through Kanon's encouragement. She embraced the school idol club, becoming its president in her second year and passing the role to Mei Yoneme in her third. Her commitment manifests in rigorous dance practices, where she reflects on her motivations during early morning sessions. She prioritizes group harmony, supporting members through choreography and leadership. Her perseverance stems from a desire to achieve self-defined goals.

Physically, Chisato has white hair styled in high side buns, dark pink eyes, and stands 155 cm tall, making her Liella!'s shortest member. Her image color is peach pink (#ff6e90), matching her penlight. She favors takoyaki, peaches, and cola, dislikes bell peppers, and adores round objects—particularly Kanon's pet owl, Manmaru, who remains wary of her.