Ruby

Main article: Ruby Hoshino/Gallery Ruby is a beautiful young girl of average height with orangish-blonde hair that she ties half of in a side ponytail on the left side of her head (much like how her late mother Ai Hoshino does), resembling her Twin Brother Aqua Hoshino and possesses pink-ruby colored eyes with a white/light pink six-star on her left eye like her late mother. As her idol career progresses, she comes to gain a six-star in her right eye as well and this becomes a permanent addition once she starts shining as brightly as Ai did on stage.[10] Her stars would sometimes blacken depending on her mental state, as well as her eyes sometimes becoming darker in color.

Ruby has been stated to resemble Ai by many people, such as Aqua Hoshino and Kana Arima where Kana herself confirmed that her keen nose in industry "can sense potential in this girl" and it reminds her of Ai. The resemblance grows stronger when she wears a purple wig, to the point that it shocks others especially Akane Kurokawa.

As a student in the Youtou High School's Performing Arts Program, she wore a white shirt adorned with a large ribbon tie and a gray, flowy skirt. Ruby also wears the black vest and the short dark blue jacket with golden stripes at the end of the sleeves and around the opening of the jacket. Her footwear also has white socks and burgundy penny loafers. Ruby describes the outfit as cute but difficult to put on. Now overwhelmed with joy as Ruby Hoshino, the daughter of her favorite idol, Ai Hoshino, takes her life to the fullest, Ruby has given herself the goal of becoming an idol singer, not only to follow in her mother's footsteps, but also to fulfill her promise to Gorou Amamiya. Unbeknownst to her, Gorou had already passed away and been reborn as her older twin brother, Aqua Hoshino.

Unlike 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. She is most apparent in the connections she makes with others. At the same time, 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, instead 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.

Ruby tends to speak her mind without a filter, often referring to Kana Arima as the "gourd girl" and the "girl who will lick a lying snitch," much to Kana's displeasure. Additionally, Ruby has utilized the "airhead sister" persona to her advantage in the media as a character she created to promote herself.

She is the biggest defender of her mother Ai's secrecy and reputation.

She is confident but now she became self-conscious and unsure. She became fat, like really fat, around 130 kilos, and it makes her doubt.