| Full Name | Kim Yun-seo |
| Stage Name | YunSeo |
| Native Name | 김윤서 |
| Birthday | July 3, 2004 |
| Age | 21 years and 2 months old |
| Zodiac Sign | Cancer |
| Birthplace | Seoul, South Korea |
| Height | 5’6″ (167 cm) |
| Weight | 92.6 lbs (42 kg) |
| Blood Type | A |
| MBTI | ESFJ |
| Education | Apgujeong High School |
| Languages | Korean, English |
| Group | BADVILLAIN (2024-present) |
| Social Media | – |