Ruby Hoshino (星ほし野の瑠る美び衣い, , Hoshino Rubii?), or more commonly known by her stage name Ruby (ルビー, Rubī?), is the deuteragonist in the Oshi no Ko manga series. Ruby was known as Sarina in her past life -- A patient with a terminal illness who became obsessed with idols. Ruby, along with her twin-brother Aquamarine Hoshino, formerly known as Gorou in his past life, is the child of the former (now defunct) B-Komachi idol, Ai Hoshino. Inspired by her mother's line of work, 