Yook Sung-jae (Korean: 육성재, English: Yook Sung-jae, Japanese: Sonje), born on May 2, 1995, debuted in 2012 as a member of the South Korean boy group BTOB. He is the youngest member of the group and initially served as both vocalist and rapper. He is currently one of the vocalists and a member of the subunit BTOB-BLUE.
