Ruby Hoshino

"Life is about doing what you want to do! If you keep talking cost this return this, you won't accomplish anything! Life can end before you get a chance to accomplish anything, it happens."

Ruby Hoshino, or more commonly known by her stage name Ruby (ルビー), 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. She, 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 member, Ai Hoshino. Inspired by her mothers' line of work, she wishes to become an idol just like her, only if her brother wasn't so overprotective of her ever since their mother died.

She's currently working with Strawberry Productions to revive B-Komachi so she could fulfill her dreams along with the support of her friends.

Appearance
Ruby Hoshino possesses features that liken her to her mother; more often than not being compared to her in many aspects. Such as her facial features and the distinct look in her eye featuring a star.

She sports blonde hair with pinkish highlights at the end. Her eyes are ruby-colored, which her mother named her after, and usually wears an idol outfit.

Personality
Unlike her brother, who is calm, calculated, and discreet, she is the polar opposite of him. She is extroverted, outgoing, loud, and the like; being the most apparent with the connections she made with others, whilst Aqua only does this to further his agenda. She doesn't share her brother's opinion of hunting down the culprit who killed their mother, rather moving on from that incident and focusing on her dreams. She persists in this notion to the point where she often conflicts with her brother's interests.

By chapter 79, Ruby became a shell of who she once was and a complete antithesis of the previous paragraph personalities. She became eerily similar if not more dark than Aqua was when he was in his darkest moments. She felt empty as well as disdainful for the murderer of Gorou, as everything she worked so hard to accomplish became worthless. The murderer stole the future she wanted and so, she resolved herself to ensure Gorou gets justice, even if it meant using her brother who finally attained true happiness with Akane.

Prologue
As Sarina, Ruby was a big fan of her now mother, Ai Hoshino. She wanted to get reincarnated as her daughter and to have a face like her. With due time, her wish gets fulfilled as she is born as Aqua's younger twin. However, only a few years after that, a crazed fan takes her mother's life and Ruby loses the idol she treasured both in her previous and current lives.

Entertainment World
After Ai's death, Ruby starts working hard towards her goal, striving to become an idol like her mom was. When she was still in middle school, she applied to a massive audition, but her application got rejected due to Aqua secretly meddling in. Shortly after, she was scouted to be an underground idol, but after serious talk with Miyako Saitou, she forms her own group and gets signed by her adoptive mother's company and Ai's former idol agency, Strawberry Productions. Ruby then joined by Kana Arima, whom Aqua asked to join in order to make Ruby's dream come true.

Dating Reality Show
Ruby and Kana were both featured on a video by the Youtuber managed by Strawberry Productions, Pieyon. After a grueling workout session, Pieyon asks them both about their idol group's name. Ruby decided to name the group after her departed mother's idol group, B-Komachi.

The First Concert
Ruby makes a Youtube channel where she and her group uploads videos with the help of B-Komachi's new member Memcho, a renowned Youtuber. They hit the milestone of 10,000 subscribers there. Later, they receive an offer from one of her brother, Aquamarine's acquaintances to participate in one of the biggest idol concerts across the country, the Japan Idol Festival. Even though Kana, another member of her idol group, disagrees with the idea of newcomers debuting in such a prestigious event, Ruby and Memcho convinces her to accept the invitation. Hence, the revived B-Komachi go on to deliver their first performance on the grand stage, earning rave reviews from fans.

2.5D Stage Play
Ruby tries to visit Aqua during his rehearsal for the stage adaptation of Tokyo Blade, but did not manage to meet him, learning that he has leave early to go someplace else. Later on, she appeared on the opening night for Tokyo Blade, watching the performance along with Miyako.

Etymology

 * The name Ruby means "lapis lazuli" (瑠) (ru), "beautiful" (美) (mi/bi) and "clothing, garment" (衣) (i).
 * Ruby's surname Hoshino means "star" (星) (hoshi) and "field, wilderness" (野) (no).

Trivia

 * Ai Hoshino (Ruby's mother) has one star in each eye where Ruby inherited a star in her left eye and her brother inherited it in his right eye.
 * She later gains an additional star in her right eye after revolving to use dirty tactics to rise in the entertainment industry.
 * The stars in Ruby's eyes grow in size when she gets aggravated and even become blackened when pushed to her limits.
 * Ruby wants to be an idol like her mother once was.