Lee Sang-hyeok (이상혁; born October 22, 2003), known professionally as Riwoo (리우), is a South Korean singer and dancer under KOZ Entertainment. He is a member of the boy group BOYNEXTDOOR.
Known For: Acting
Birthday: 2003-10-22
Place of Birth: Seoul, South Korea
Also Known As: Lee Sang-hyeok, 이상혁, 리우, BOYNEXTDOOR, 보이넥스트도어