Ruby Hoshino Personality: A Driven Idol in the Making

Updated: Monday, December 22, 2025

MBTI

ENFP

Enneagram

7w6

Alignment

Chaotic Good

Ruby Hoshino is the reincarnation of Sarina Tendouji, a 12-year-old girl who died of cancer and was a fan of Ai Hoshino, a famous pop idol. She is reborn as the daughter of Ai Hoshino and the twin sister of Aquamarine Hoshino, who is the reincarnation of Gorou Amamiya, Sarina's doctor and another fan of Ai Hoshino.

Ruby’s Personality

Ruby Hoshino is a cheerful, energetic, optimistic, and outgoing girl who loves singing, dancing, and making friends. She is also kind, compassionate, empathetic, and loyal to those she cares about. She is not afraid to express her emotions and opinions, and she can be impulsive, reckless, and stubborn at times. She is very determined and hardworking, always striving to improve herself and achieve her goals.

Ruby was born with a rare condition called “Oshi no Ko Syndrome”, which grants her exceptional talent and charisma, but also shortens her lifespan. She inherited this condition from her mother, Ai Hoshino, who was the most popular idol in Japan before her death. Ruby grew up idolizing her mother and wanting to follow in her footsteps. She also inherited her mother’s appearance, voice, and personality traits, which made her stand out from other children.

Ruby’s life changed drastically when she met her father, Dr. Gorō Amamiya, who had reincarnated into her body after dying in a car accident. Gorō was a brilliant surgeon who had saved many lives, but he was also cold, distant, and cynical. He had no interest in idols or entertainment, and he only agreed to become Ruby’s father to protect her from the dangers of the idol industry. He also wanted to find a way to cure her condition and extend her lifespan.

Ruby and Gorō had a rocky start, as they had to share the same body and mind. They often clashed over their different views and preferences, and they had to learn to cooperate and compromise. Ruby was initially annoyed by Gorō’s interference and criticism, but she gradually grew to respect and appreciate him. She also helped him to open up and enjoy life more. She taught him how to sing, dance, and smile, and she introduced him to her friends and idols. She also showed him the joy and meaning of being an idol, and how to connect with the fans and the audience.

Ruby’s dream of becoming an idol came true when she auditioned for the agency that her mother belonged to. She impressed the judges with her talent and charisma, and she was accepted as a trainee. She was assigned to the same unit as her mother’s former rival, Akane Kurokawa, who became her mentor and friend. She also met other idols and trainees, such as Aqua Hoshino, her half-sister and fellow Oshi no Ko; Mem-Cho, her manager and supporter; and Hikaru Kamiki, her childhood friend and crush.

Ruby faced many challenges and hardships as an idol, such as the pressure of expectations, the competition of rivals, the manipulation of the media, and the threats of anti-fans. She also had to deal with the secrets and mysteries of her condition, her mother’s death, and her father’s past. She had to balance her idol activities with her school and family life, and she had to hide her dual identity from the public. She also had to cope with the reality of her limited lifespan, and the possibility of losing her father and her friends.

Ruby overcame these difficulties with the help of her father, her friends, and her fans. She also relied on her own strength and courage, and her passion and love for being an idol. She never gave up on her dream, and she always tried to do her best and have fun. She also wanted to make others happy, and to spread her positive energy and message to the world. She became a popular and successful idol, and she earned the admiration and affection of many people.

Relationships

Dr. Gorō Amamiya: Ruby’s father and the person who shares her body and mind. They have a close and complex relationship, as they are both family and partners. They care deeply for each other, and they support and protect each other. They also influence and change each other, as they learn from each other’s experiences and perspectives. They sometimes argue and disagree, but they always make up and cooperate. They have a mutual respect and trust, and they share a strong bond.
Ai Hoshino: Ruby’s mother and the idol who inspired her. Ruby loves and admires her mother, and she wants to be like her. She inherited her mother’s talent, charisma, appearance, voice, and personality traits. She also inherited her mother’s condition, which shortens her lifespan. She feels a connection and a responsibility to her mother, and she wants to honor her legacy and fulfill her wishes. She also wants to know more about her mother’s life and death, and to find out the truth behind them.
Akane Kurokawa: Ruby’s mentor and friend, and the leader of the idol unit that Ruby belongs to. Akane is a veteran idol who was Ai Hoshino’s rival and friend. She is strict, serious, and professional, but she is also kind, caring, and supportive. She recognizes Ruby’s potential and talent, and she helps her to grow and improve as an idol. She also treats her as a friend and a junior, and she shares her knowledge and experience with her. She respects and trusts Ruby, and she considers her as her successor and partner.
Aqua Hoshino: Ruby’s half-sister and fellow Oshi no Ko, and the daughter of Ai Hoshino and a mysterious man. Aqua is a genius idol who debuted at a young age, and who is considered as the next Ai Hoshino. She is calm, cool, and confident, but she is also aloof, arrogant, and ruthless. She has a rivalry and a fascination with Ruby, and she challenges and provokes her. She also has a hidden interest and affection for Ruby, and she wants to get closer to her. She shares a connection and a secret with Ruby, and she is one of the few people who knows about her condition and her father.
Mem-Cho: Ruby’s manager and supporter, and a former idol who was Ai Hoshino’s fan. Mem-Cho is a cheerful, friendly, and enthusiastic woman who loves idols and entertainment. She is loyal, reliable, and helpful, and she takes care of Ruby’s needs and schedules. She also encourages and advises Ruby, and she cheers her on. She is fond and proud of Ruby, and she sees her as a daughter and a friend. She also knows about Ruby’s condition and her father, and she keeps their secret and protects them.
Hikaru Kamiki: Ruby’s childhood friend and crush, and a popular actor who is also an idol fan. Hikaru is a handsome, charming, and talented young man who is adored by many people. He is friendly, polite, and gentle, but he is also shy, awkward, and insecure. He has a crush on Ruby, and he is always nervous and flustered around her. He also supports and admires Ruby, and he is one of her biggest fans. He is unaware of Ruby’s condition and her father, and he is confused and curious about her dual identity.

Ruby’s Quotes

Ruby Hoshino has many memorable and meaningful quotes that reveal her personality and thoughts. Some of them are:

"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's philosophy here is clear: seize the day and follow your passions without overthinking the costs or risks. It's a reflection of her past as Sarina, who passed away before achieving her dreams, emphasizing the urgency of living life to the fullest.

"I’m not doing this for anyone else. I’m doing this for myself. I want to be an idol. I want to be like mom. I want to be the best."

This quote captures Ruby's self-driven ambition and her deep admiration for her mother, Ai. It highlights her determination to excel in her idol career for her own fulfillment, showcasing a blend of personal ambition and familial inspiration.

"I don’t need your permission or approval. I don’t need your protection or guidance. I don’t need you. I can do this on my own."

Here, Ruby expresses her strong sense of independence and self-reliance, possibly to the point of stubbornness. Her statement reflects a mix of defiance towards Aqua and a youthful desire to prove her capabilities, while perhaps overlooking the value of guidance and support.

"I’m not a liar. I’m an actress. I’m a performer. I’m an idol. I’m whatever I want to be. I’m whatever they want me to be."

Ruby's words reveal the complexities of her identity as a performer. She sees herself as adaptable and multifaceted, capable of being what her audience desires. This quote touches on the themes of authenticity versus performance in the life of an idol.

"I’m sorry. I’m sorry for everything. I’m sorry for being selfish. I’m sorry for being rude. I’m sorry for being ungrateful. I’m sorry for being a bad sister. I’m sorry for being a bad daughter. I’m sorry for being a bad person."

This poignant quote shows a moment of self-awareness and maturity in Ruby. Her apologies reflect her recognition of past mistakes, demonstrating growth, vulnerability, and a desire to make amends, a significant step in her personal development.

Find out how you match with Ruby Hoshino. Take the

Other Characters

Check out the personalities of other characters from Oshi No Ko.