Character appearances }
Main •
Lee Ji-ah as Shim Su-ryeon / Na Ae-kyo : Shim Su-ryeon: A graceful, elegant woman who is kind and thoughtful, despite her immense wealth. She and her husband, Joo Dan-tae, live in the penthouse of Hera Palace, making her the queen of the building's social clique. Learning of her husband's affair with Cheon Seo-jin and his involvement in the death of her daughter Min Seol-ah, she is determined to take revenge against him. Later in the series, she is also revealed to be the biological mother of Joo Seok-kyung. : Na Ae-kyo: Business partner and mistress to Joo Dan-tae, lover to Jung Doo-man and the biological mother of Joo Seok-hoon. She bears a striking resemblance to Shim Su-ryeon and has a butterfly tattoo on her back. •
Kim So-yeon as Cheon Seo-jin : One of the primary antagonists of the series. She is a wealthy woman who is the epitome of extravagant arrogance and harbors warped ambitions. She would do anything for power, money, and pride. She and Oh Yoon-hee have been bitter rivals since childhood. She pushes her daughter, Ha Eun-byeol, to sing in order to beat Oh Yoon-hee's daughter, Bae Ro-na, who is more talented than her. •
Eugene as Oh Yoon-hee : A woman whose dreams have been stunted by her lack of money and power. With gritted teeth, she took on any job and humiliation to support her daughter's ambitions of becoming an opera singer. She and Cheon Seo-jin have been bitter rivals since childhood. She does everything in her power to move up socially and financially so that her daughter, Bae Ro-na, is able to enter the prestigious Cheong-ah Arts School.
Supporting Shim Su-ryeon/Na Ae-kyo's family •
Kim Young-dae as Joo Seok-hoon (Baek Seok-hoon) : Joo Dan-tae (Baek Joon-ki) and Na Ae-kyo's son; Cheon Seo-jin and Shim Su-ryeon's stepson; Ha Eun-byeol, Joo Seok-kyung and Min Seol-ah's step brother. He is a calm, self-contained, and observant piano student who protects his twin sister, Seok-kyung, from their abusive father. Because of his father's evil deeds, he slowly becomes resentful towards him as the series progresses. He falls in love with Bae Ro-na, despite Ha Eun-byeol's jealousy and his twin sister's vehement disapproval. •
Han Ji-hyun as Joo Seok-kyung (Jo Seok-Kyung) :Shim Su-ryeon's biological twin daughter; Min Seol-Ah's younger fraternal twin sister and Joo Seok-hoon's step sister. Seok-kyung was abducted by Joo Dan-tae and ended up as Seok-hoon's twin sister at birth. As a result, this caused her to believe that her own mother is the stepmother. She is a cunning, selfish, and scheming soprano student. She has been physically and emotionally abused by Joo Dan-tae; therefore, she bullied her classmates mercilessly, took her stepmother Su-ryeon for granted, and manipulated Seok-hoon for her needs. •
Jo Soo-min as Anna Lee / Min Seol-ah (Jo Seol-ah) : Shim Su-ryeon's biological twin daughter; Joo Seok-kyung's older fraternal twin sister; and Joo Seok-hoon's step sister; Alex and Logan Lee's adopted sister. Seol-ah was switched out with Hye-in at birth, and abandoned as an orphan. She is intelligent, humane, compassionate, hard-working, and has the talent of a gifted soprano singer. She disguises herself as Anna Lee, a math tutor who graduated from
UCLA, and tutors the Hera Palace children as she is in desperate need of money. She later enters the Cheong-ah Art School but is bullied and ostracized by her classmates including her twin sister. She dies under mysterious circumstances at the Hera Palace after attempting to expose the bullying and admission manipulation at the school. • Na So-ye as Joo Hye-in (Kim Hye-in) : Kim Mi-sook's biological daughter; raised by Shim Su-ryeon. She was switched out with Seol-ah at birth. As she was born sickly, Joo Dan-tae tried to kill her in order to obtain her land and properties but Su-ryeon saves her and sends her to safety to America where she currently resides.
Cheon Seo-jin's family •
Um Ki-joon as Joo Dan-tae (fake identity) / Baek Joon-ki (real identity) : One of the primary antagonists of the series. Former husband and nemesis of Shim Su-ryeon, former lover of Na Ae-kyo, current husband of Cheon Seo-jin. He is the biological father of Joo Seok-hoon (Baek Seok-hoon); the stepfather of Ha Eun-byeol, Joo Seok-kyung and Min Seol-ah and the adoptive father of Joo Hye-in. As the chairman of J King Holding who rakes in money with every investment he makes, he only cares about making more. He is a cruel, greedy, sadistic, and manipulative control freak who will not hesitate to kill anyone who gets into his way. His goal is to build a luxury building called "Joo Dan-tae Village" in the Cheon-su district. He was responsible for the events of Su-ryeon's tragic past such as murdering her previous husband, separating her twin daughters away from her- one was switched with another child eventually abandoned while another believes the mother is the stepmother. •
Choi Ye-bin as Ha Eun-byeol : Cheon Seo-jin's daughter; Joo Dan-tae (Baek Joon-ki)'s stepdaughter. She is constantly being pressured by her mother to sing better than Bae Ro-na. She was in love with Joo Seok-hoon, who doesn't reciprocate her feelings. At first, Eun-byeol appears to be nice - however, due to her mother's expectations and Joo Seok-kyung's influence, her personality changes drastically. Although she is cruel like her mother, she is easily tormented by manipulative people. The pressure caused by her mother led her to become
psychopathic, and she is diagnosed with
imposter syndrome. She develops a hatred of Bae Ro-na. • as Cheon Myung-soo : Seo-jin's father. He is intent on keeping Cheong-ah Arts School's reputation intact at all costs. Due to this he tries to give the foundation to Seo-young after Seo-jin's divorce as he learned of Seo-jin's affair. • Ha Min as Kang Ok-gyo : Seo-jin's stepmother who fails to take care of Eun-byeol while she was in prison. • Shin Seo-hyun as Cheon Seo-young : Seo-jin's younger half-sister who is later caught having an affair with another man behind her husband's back, which Seo-jin uses against her. • Ahn Tae-hwan as Seo-young's husband : Seo-jin's brother-in-law.
Oh Yoon-hee's family •
Yoon Jong-hoon as Ha Yoon-cheol : Former husband of Cheon Seo-jin and current husband and first love of Oh Yoon Hee. He's the father of Bae Ro-na. An ambitious man who believes that a man must hold wealth and power. He is the head of surgery in the VIP department of a hospital. He divorces Seo-jin at the end of season 1, and marries Yoon-hee in season 2, his first love. •
Kim Hyun-soo as Bae Ro-na : Ha Yoon-cheol and Oh Yoon-hee's daughter. She is a gifted soprano singer who wants to do her best in school and enter
Seoul National University. She was scammed by Ma Du-ki and was on the waiting list to enter Cheong-ah High School, but was cast off the waiting list after Min Seol-ah's death. Similar to Seol-ah, she deals with bullying and ostracization by her classmates and the other Hera Palace kids, but she is able to stand up for herself. •
Hwang Young-hee as Yoon-hee's mother-in-law : She was paid by Cheon Seo-jin to make a scene at Hera Palace, accuse Yoon-hee of not letting her visit her granddaughter, Bae Ro-na, and blames Yoon-hee for the death of her son. She is a woman who would do anything for money. • Choi Won-young as Bae Ho-cheol : Oh Yoon-hee's first husband. It is later revealed that he cheated on Yoon-hee. He died prior to the events in the series.
Kang Ma-ri and family •
Shin Eun-kyung as Kang Ma-ri : A woman who has recently come into wealth and leads a secretive double life. She lies and tells everyone that her husband, Yoo Jenny's father, is doing business in Dubai but in reality, he is in prison. She bribes the guards with expensive goods to let her see her husband in prison. She advises her daughter to become friends with Joo Seok-hoon, Joo Seok-kyung, Lee Min-hyeok, and Ha Eun-byeol so that she can get on the good side of the wealthy people of Hera Palace. •
Jin Ji-hee as Yoo Jenny : Kang Ma-ri and Yoo Dong-pil's daughter. She went to the same middle school as Bae Ro-na and were enemies. She accused Ron-Na of poisoning her drink which nearly caused Ro-na to be expelled from school. However, at the end of season 1, she started to warm up with Ro-na by giving her food when Ro-na was accused to be the daughter of a murderer. Later on, she started to develop a friendship with Ro-na. •
Park Ho-san as Yoo Dong-pil : Cheon Seo-jin's personal secretary. • Kim Jae-hong as Secretary Hong : The secretary of Logan Lee. • as Jin Bun-hong : She is undercover for Logan Lee working as a personal tutor and caretaker for Eun-byeol. As part of her job, she relates information to Yoon-hee and Logan. She becomes affectionate towards Ha Eun-byeol due to a traumatic past about her daughter. •
On Joo-wan as Baek Joon-ki (Fake Identity)/Joo Dan-tae (Real Identity) : Initially named "Joon-ki", a mysterious figure who appeared at the end of Season 2, sitting beside Logan Lee during his return flight to South Korea and was last seen hastily leaving Logan's car moments before the explosion. In Season 3, it was revealed (through an extended scene with Logan inside the plane) that Baek Joon-ki's real name is Joo Dan-tae, and that the person who has long been using his identity was actually a serial killer named Baek Joon-ki (hence his "Mister Baek" moniker), who also stole his parents' fortune after killing them in Japan. He is the only person who knows Joo Dan-tae's darkest secret. • Lee So-yeon as Kim Mi-sook : Joo Hye-in's biological mother who abandoned Hye-in for money and was murdered by Joo Dan-tae. •
Oh Min-ae as Ms. Byeon •
Han Soo-ah as Song Ye-ri •
Song Duk-ho as Ye Tae-sool
Special appearances • as Congressman Jo Sang-heon (Ep. 1–2, 4–5) : He attempted to kill Su-Ryeon when she found out about his fraud but was later murdered. • Ki Tae-hwa as Su-ryeon's ex-husband (Ep. 3) : He was Su-ryeon's previous husband prior her marriage to Joo Dan-tae, a gifted pianist who was murdered by Joo Dan-tae and gunmen. He is the biological father of Min Seol-ah and Joo Seok-kyung. • Han Seung-soo as Orphanage Director Min Hyung-sik (Ep. 3, 5) •
Kim Byung-hyun as Joo Dan-tae's best friend pitcher (Ep. 12) • Ki Eun-se as Journalist Kim Jung-min (Ep. 20–21) • Kim Sa-kwon as Detective in charge of Oh Yoon-hee's investigation (Ep. 20–21) •
Jun Jin as Wedding couple (Ep. 1) • Ryu Yi-seo as Wedding couple (Ep. 1) •
Lee Sang-woo as Reporter Son Hyung-jin (Ep. 2, 4) •
Bada as Park Young-ran (Ep. 2) • Ki Eun-se as Journalist Kim Jung-min (Ep. 2, 7) •
Yeon Min-ji as Alumni of Yoon-hee and Seo-jin (Ep. 3) •
Nam Bo-ra as Pianist for Bae Ro-na (Ep. 5, 7) •
Lee Si-eon as Detective (Ep. 6) •
Kim Kwang-kyu as Fake detective (Ep. 8) : An actor hired by Dan-tae to act as a detective. •
Jo Jae-yoon as Hwang Geum-bong (Ep. 9–12) : A real estate agent well-versed with the upcoming redevelopment of Cheonjin District. •
Kim Dong-young as Detective (Ep. 11–12) • Kim Soo-hwan as Detective (Ep. 11–12) •
Yoo Jun-sang as Jung Doo-man (Ep. 12–13) : A politician and boyfriend of Na Ae-kyo. •
On Joo-wan as Baek Joon-ki / Joo Dan-tae (Ep. 13) •
Choi Byung-mo as Judge (Ep. 13) •
Lee Sang-min as Prison Guard Jo (Ep. 13) •
Park Sang-myun as Bang Chi-soon (Ep. 1) : Boss of men's prison cell. • Jung Young-ju as Boss of women's prison cell (Ep. 1) • Kwon Tae-won as Chief Justice Jung (Ep. 1) •
Lee Sang-min as Prison Guard Jo (Ep. 1) • Yoo Yeon as Shim Su-ryeon's psychiatrist (Ep. 1) • Nam Sung-jin as Joo Dan-tae's father (Ep. 3, 7) •
Sung Ji-ru as Oh Man-sik (Ep. 3, 6) •
Lee Jae-woo as Police officer (Ep. 5) • Song Young-gyu as Kang Sin-mo (Ep. 6–7) : Vice Minister of Education. • Yoon Seok-hwa as Logan Lee's Grandmother (Ep. 7–9) •
Shin Sung-woo as Clark Lee (Ep. 7–8) •
Lee Yu-bi as Boss of girl's juvenile hall torments Joo Seok-kyung. (Ep. 7–8) • Kim Joo-hee as News Anchor (Ep. 7) • Kim Se-hee as News Anchor (Ep. 10, 12) • Yoon Joo-man as Loan Shark (Ep. 11–12) •
Lee Tae-sung as Prosecutor (Ep. 11–12, 14) •
Seo Ji-seok as Detective (Ep. 11–13) •
Shin Seung-hwan as Doctor (Ep. 12–13) •
Heo Jung-min as Doctor (Ep. 12–13) • Tae Hang-ho as Judge (Ep. 14) • Kim Myung-soo as Cheon Seo-jin's lawyer (Ep. 14) •
Lee Hee-jin as Massage Customer's Daughter (Ep. 14) • Kim Do-gun as Lee Kyu-jin's secretary •
Jang Sung-kyu as Defrauded Person (Ep. 14) • Kim Beop-rae as Restaurant Owner (Ep. 14) • Ahn Hye-kyung as Officer Lee Nam-sook (Ep. 14) •
Choi Yoon-so as Mental Hospital Nurse (Ep. 14) •
Bewhy as Lee Byung-hoon (Ep. 14) ==Production==