
LightSum [라잇썸 – ライトサム]
- Debut (Y-M-D): 21-06-10
- Label: Cube Entertainment
- Music Videos:
- Albums:
- Korean: Vanilla [Single Album], Light A Wish [Single Album], Into The Light [Mini Album]
- Fan Name: SUMIT (썸잇) (Lightsum [SUM] + becoming one through the medium [it])
- Logo:

Members:

- Stage Name (Hangul): Sangah (상아)
- Position: Rap, Dance
- Real Name: Yoon Sangah (윤상아)
- Birthday (Y-M-D): 02-09-04
- Nationality: Korean
- Height: N/A
- Blood Type: N/A

- Stage Name (Hangul): Chowon (초원)
- Position: Vocal
- Real Name: Han Chowon (한초원)
- Birthday (Y-M-D): 02-09-16
- Nationality: Korean
- Height: 168cm | 5ft 6in
- Blood Type: O

- Stage Name (Hangul): Nayoung (나영)
- Position: Vocal, Dance
- Real Name: Kim Nayoung (김나영)
- Birthday (Y-M-D): 02-11-30
- Nationality: Korean
- Height: 155cm | 5ft 1in
- Blood Type: O

- Stage Name (Hangul): Hina (히나)
- Position: Vocal
- Real Name: Nagai Hina (ナガイ ヒナ)
- Birthday (Y-M-D): 03-04-07
- Nationality: Japanese
- Height: N/A
- Blood Type: N/A

- Stage Name (Hangul): Juhyeon (주현)
- Position: Leader, Dance, Vocal
- Real Name: Lee Juhyeon (이주현)
- Birthday (Y-M-D): 04-04-08
- Nationality: Korean
- Height: 171cm | 5ft 7in
- Blood Type: AB

- Stage Name (Hangul): Yujeong (유정)
- Position: Vocal
- Real Name: Lee Yujeong (이유정)
- Birthday (Y-M-D): 04-06-14
- Nationality: Korean
- Height: 160 cm | 5ft 2in
- Blood Type: AB
Former Members:

- From: July 2021 – October 2022
- Stage Name (Hangul): Huiyeon (휘연)
- Position: Vocal
- Real Name: Oh Huiyeon (오휘연)
- Birthday (Y-M-D): 05-08-01
- Nationality: Korean
- Height: N/A
- Blood Type: N/A

- From: July 2021 – October 2022
- Stage Name (Hangul): Jian (지안)
- Position: Rap, Vocal
- Real Name: Kim Jian (김지안)
- Birthday (Y-M-D): 06-11-04
- Nationality: Korean
- Height: N/A
- Blood Type: N/A