**Background:** Ruby is a first year student who is the younger sister of Dia Kurosawa, who she shares a strong bond with. She is from an old family involved in fishing management whose name is well-known around the area. The Kurosawa family also owns a number of companies including real estate, entertainment, human resources and restaurant management. Ruby is almost always nearby her best friend, Hanamaru Kunikida. In the anime, in the first episode, Ruby is shown to display a big interest in school idols. Season 1 Episode 4 shows that she used to be a fan of school idols, sharing this hobby with Dia, although something caused her older sister to seemingly lose that interest, which is revealed in Season 1 Episodes 6, 8 and 9 to be Dia's failure as a school idol. Ruby's love for school idols remained intact, but the event made her secretly keep it away from her sister. She later joins Aqours in Season 1 Episode 4, after counting with her sister's support. <hr> **Personality**: Ruby is very shy and timid, which makes it hard for her to get along with other people. She has a tendency to utter or scream "Pigii!!!" when she doesn't like something; in the event she screams, her face will turn red as she does so. Although she is fearful and easily upset, she does have a tough interior forged by her role as the daughter of a rich, well-known family. She meets Leah Kazuno in Tokyo, who she becomes very close with. From a different perspective, Ruby is adaptable and mostly admired by her friends, and they support her no matter what; despite the fact the Second Years are considered "the heart" of Aqours, Ruby does not have difficulty getting along with the rest of the group unlike her fellow First Years' or the Third Years', as seen in Season 2 Episode 2. Ruby also speaks in the third person from time to time, just like Hanamaru. However, she tends to use "watashi" as a first-person pronoun. Due to the strong bond she shares with her sister Dia, Ruby will immediately display her tough interior and defend her sister when a negative point of her is brought up, as seen in Season 2 Episode 8. Ruby is also shown to have a playful and mischievous side of her when she teases Yoshiko Tsushima's Fallen Angel behavior and her embarrassing moments (alongside Hanamaru), which annoys Yoshiko all the time. She also despises spicy food, as seen in Season 1 Episode 10, when she eats a takoyaki filled with tabasco sauce instead of octopus sauce. <hr> **Appearance:** Ruby is short with a slim figure and semi-long red hair which she ties into twintails and turquoise eyes.

- Before starting middle school, Ruby had long hair - Ruby has androphobia (fear of men) and has never talked to any man besides her own father (Official Dengeki G bio/introduction, School Idol Diary/Aqours’ Sea Side Diary)