Height 158 cm (5'2") Ai Hoshino's daughter, and the younger twin sister of Aquamarine Hoshino.

Spoiler

She was previously a patient named Sarina under Goro's care. Due to her illness, she was wheelchair-bound. After discovering B-Komachi, she had always aspired to be an idol although her condition kept her from achieving her dream. Since being reincarnated as Ruby, she is now working towards her dream of being an idol like Ai. To do so she's currently working with Strawberry Productions to revive B-Komachi along with Arima Kana and Memcho.