Ruka

Ruka's full name is Kawai Ruka (河井 瑠花). She was born on March 20, 2002, in Yamaguchi Prefecture, Japan, making her the oldest member of BABYMONSTER. Source: KProfiles / Wikipedia

Before joining YG Entertainment, Ruka debuted in 2017 as one of the founding members of the Japanese idol group Shibu3 Project. She left the group in 2018 to pursue training in South Korea. Source: BABYMONSTER Wiki / Wikipedia

Ruka joined YG Entertainment in 2018, giving her one of the longest trainee periods in BABYMONSTER at approximately six years before debut. Source: Wikipedia / KProfiles

She auditioned for YG with DJ Khaled's "Top Off" featuring JAY-Z, Future, and Beyoncé, impressing the company with her confidence and hip-hop style. Source: KProfiles

Dance has been part of Ruka's life since she was six years old, and she has said she wants to keep dancing for the rest of her life. Source: Teen Vogue / KProfiles

YG founder Yang Hyun-suk once revealed that he had never needed to critique Ruka's dancing, citing her exceptional understanding of movement and rhythm. Choreographer Leejung Lee has similarly praised her years of dance experience and technical precision. Source: KProfiles

During BABYMONSTER's member introductions, Ruka was the final member to be revealed by YG Entertainment, completing the group's seven-member lineup. Source: BABYMONSTER Wiki / Wikipedia

Ruka and fellow member Asa became the first Japanese female idols to debut under YG Entertainment, marking an important milestone in the company's history. Source: Wikipedia / KProfiles

She speaks Japanese, Korean, and English, and has shared that adapting to life in Seoul became much easier thanks to the support of her fellow international members. Source: Teen Vogue / KProfiles

Fellow members often describe Ruka as the group's dependable "big sister." Even though BABYMONSTER has no official leader, she's known for naturally taking care of the younger members. Source: Teen Vogue / KProfiles

Ruka enjoys Pilates as part of her fitness routine and says one of the first things she does every morning is drink a glass of milk. Source: KProfiles

If she hadn't become an idol, Ruka has said she would have liked to become a fashion designer and even dreamed of owning her own clothing brand someday. Source: KProfiles / BABYMONSTER Children's Day Profile

She loves mala soup, ice cream, and lists Titanic as one of her favorite movies. Her favorite Sanrio character is Pochacco. Source: KProfiles

During BABYMONSTER content, Ruka won the challenge to determine which member knows the others best, reflecting how closely she pays attention to everyone in the group. Source: KProfiles

In interviews with Teen Vogue, Ruka shared that the trainees spent nearly every day together, relying on one another through language barriers, homesickness, and demanding monthly evaluations before debut. She credited those experiences with creating the close bond the members share today.

Fans often praise Ruka for her smooth hip-hop style, charismatic stage presence, and low-toned rap voice, qualities that have established her as one of BABYMONSTER's strongest performers. Source: KProfiles / BABYMONSTER Wiki

Despite being the oldest member, Ruka is known for her playful personality and often laughs the loudest during behind-the-scenes content, making her one of the group's biggest mood makers. Source: KProfiles / Fan content