Arisa Ayase is the younger sister of Eli Ayase and a close friend of Yukiho Kosaka. Her Russian heritage comes from her grandmother, and she grew up in Russia, leading to limited knowledge of Japanese daily customs—such as once buying oden from a vending machine thinking it was a drink. She has light blonde hair falling to her shoulders, blue eyes, and a slim build, and a snowflake-shaped hairpin often adorns the right side of her hair. Arisa intensely admires the school idol group μ's, particularly her sister Eli and Umi Sonoda. She attends their performances multiple times, rewatches recordings constantly, and describes how their music sparks strong positive feelings. Her personality blends cheerfulness with bluntness; she openly questions Eli's student council speech, doubting it reflects Eli’s true wishes. Arisa shares a close friendship with Yukiho, and they watch μ's performances together, study for entrance exams, and regularly hang out. After both pass exams for Otonokizaka Academy, Arisa initially plans to join μ's but later tells Honoka that she and Yukiho will form a new idol unit instead, concluding that the μ's they love is complete without them. She remains an active audience member during key events like the Love Live! competition and graduation shows, and in the movie timeline, she and Yukiho attend μ's final major concert and are later shown as members of the Idol Research Club at Otonokizaka High School.