Ruka
Kawai Ruka (河井瑠花)- Korean Name:Kawai Ruka (河井瑠花)
- Nickname:Ruka
- Birthday:March 20, 2002
- Nationality:Japanese
- Zodiac Sign:Pisces
- Height:N/A
- Weight:N/A
- MBTI Type:ISTJ & ISFP
- Blood Type:O
- Occupation:Main Dancer, Rapper
- Years Active:2017-2018,2023-present
- Agency:YG Entertainment
- SNS:@rukakawai (Inactive)
Biography
RUKA (루카), born Kawai Ruka (河井瑠花) on March 20, 2002, in Japan, is the main dancer and lead rapper of BABYMONSTER under YG Entertainment.
She is known for her sharp dance technique, powerful stage control, and charismatic performance style.
Early Life & Background
- Born and raised in Japan
- Trained in dance from a young age
- Former member of a Japanese dance group before joining YG
- Moved to South Korea to pursue K-pop training
- Fluent in Japanese, proficient in Korean
- Ruka’s early exposure to professional dance environments helped her develop strong fundamentals and stage confidence.

The Path to BABYMONSTER
Ruka joined YG Entertainment as a trainee and became one of the longest-trained members of BABYMONSTER, undergoing approximately 6 years of training.
Throughout YG’s pre-debut evaluation content, Ruka stood out as:
- The most performance-ready trainee
- A reliable leader figure during practices
- A dancer with precise control and natural groove
Unique Fact: Ruka is often referred to by fans as the group’s “performance captain” due to her discipline and experience.
Career Milestones & Achievements
Pre-Debut Era (2018–2023)
- Revealed through YG’s BABYMONSTER pre-debut project
- Praised by YG producers for professionalism and consistency
- Built a solid international fanbase before debut
Official Debut & Breakthrough (2023–2024)
BABYMONSTER officially debuted on November 27, 2023, with “Batter Up.”
Global Activities & Current Status (2024–2025)
- Participated in releases: Sheesh, Forever, Like That
- Took part in BABYMONSTER’s first world tour “Hello Monsters”
- Frequently highlighted in dance breaks and performance stages

Personal Life & Personality
- Personality: Confident, energetic, outspoken, playful
- Known among members as reliable and motivating
- Interests: Dancing, fitness, stage directing
- Languages: Japanese (native), Korean (fluent)
- Despite her strong image on stage, Ruka is often described as friendly and humorous off-stage.
Controversies & Challenges
Long Trainee Period
Ruka endured one of the longest trainee periods in the group, facing uncertainty and pressure.
How She Overcame It: She focused on consistency and leadership, earning trust from trainers and fans alike.

Discography & Filmography
BABYMONSTER Discography
📀 Singles & Digital Releases
| Year | Title | Type | Notes |
|---|---|---|---|
| 2023 | DREAM | Pre-debut Digital Single | Pre-release song, introduced members |
| 2023 | BATTER UP | Digital Single | Official debut song |
| 2024 | Stuck In The Middle | Digital Single | Ballad-focused, vocal showcase |
| 2024 | SHEESH | Digital Single | Hip-hop concept, strong performance focus |
💿 EP / Mini Album
| Year | Album | Type | Title Tracks |
|---|---|---|---|
| 2024 | BABYMONS7ER | Mini Album | SHEESH, Stuck In The Middle, BATTER UP (ver.) |
Variety & Media Appearances
📺 Reality & Variety Shows
| Year | Program | Platform / Channel | Notes |
|---|---|---|---|
| 2023 | Last Evaluation | YouTube (YG Entertainment) | Pre-debut survival-style series introducing all members |
| 2023 | BABYMONSTER – Behind the Scenes | YouTube | Training, recording sessions, and debut preparations |
| 2024 | BABYMONSTER Documentary | YouTube | Follows the group’s journey after debut |
| 2024 | Weekly Idol | MBC every1 | First major Korean variety show appearance |
| 2024 | Idol Radio | MBC Radio | Talk show highlighting members’ personalities |
Fun Facts
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Along with Asa, Ruka is one of the first Japanese female idols to debut under YG Entertainment.
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One of the dance instructors, LEEJUNG, praised Ruka for her dance experience and understanding. The former CEO of YG Entertainment was so impressed by her skills that he never felt the need to advise her on dancing.
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She sang DJ Khaled’s “Top Off” featuring JAY Z, Future, and Beyoncé during her audition.
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Ruka's favorite food is Mala soup.
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If Ruka wasn't an idol, she'd be a clothing fashion designer.
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Ruka is credited as a songwriter of their song "Love In My Heart".
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She appeared in the “Happy Halloween!” MV by Ueda Atsumi.

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