Unlike her older twin brother Aqua, who is calm, calculated, and discreet. Ruby is the polar opposite of him as she is extroverted, outgoing, loud, optimistic, and communicative compared to her brooding brother. As she found out her "sensei" Gorou was killed by an Unknown stalker who killed her mother the famous Idol Ai Hoshino when she was young at her house, as she swore to take revenge on the stalker and fulfill her mothers goal to be a Popular Idol she is also a liar and manipulator