Yoon Sang Ah, known simply as Sangah, is a South Korean singer, dancer and member of LIGHTSUM (라잇썸). She graduated from Inseong Girls’ High School, and before debuting, she took classes at PinkM Dance Academy and A-Root Dance Academy. She officially debuted in June 2021 as the group's leader, lead dancer and main rapper with their first single, "Vanilla". They are managed by CUBE Entertainment (큐브엔터테인먼트). (Source: MyDramaList) Watch drama online for free.