they have sold over 100,000 copies. Today, NRG is widely credited as one of the pioneers of the Korean Wave (Korean Hallyu) that first swept through Asia in the late 1990s. In 1999, Lee left the group to pursue a career in acting and hosting, while Chun took a less visible role in the group by choreographing their dance routines and writing and composing rather than performing. They released their third album, NRG 003 as well as a Christmas album that year titled Kiss In Christmas. 2000-2001: Kim Hwan-sung’s death, Sorrow, and temporary hiatus Tragedy struck when Kim died suddenly of a virus infection on June 15, 2000. He had been admitted to the hospital on June 6 but his condition quickly deteriorated to the point where he was placed on life support. The members went on a one-year hiatus to mourn his death and considered disbanding permanently at one point. NRG's fourth album Sorrow (悲) was released in 2001 with the title track written for them by H.O.T. member Kangta. In August 2001, NRG held their first concert in Korea, paying tribute to Hwan-sung by performing "Good Bye My Friend" and "Antonio" (Hwan-sung's nickname) which was written and composed by Myung-hoon. 2002–2005: Return with Hit Song, first number-one song, New Radiancy 6 Group, and Sung-hoon's Departure Almost four years after the death of Kim Hwan-sung, NRG returned with their fifth album Hit Song in 2003. The lead single "Hit Song" earned the group their first ever #1 win on a music program. They were also named in the Teen's Choice Top 10 Singers (ko) at the MBC Gayo Daejejeon music awards. During the ceremony, the members dedicated their win to Kim. In 2004, NRG released their sixth album New Radiancy 6 Group. The title track placed 4th in the pop charts as the World Cup neared, and was fitting for the occasion. However, the song, "Hurray For A Virile Son Of Korea" did not chart. Soon afterward, Moon announced his departure for unspecified reasons and remained out of the public eye for over a decade; he appeared on the SBS show Star Couple (ko) with his wife in 2012 and revealed that they had a son, although they have since divorced. NRG promoted as a three-member group once again. 2005–2015: One of Five and temporary disbandment In 2005, the now three-member NRG released their seventh album One of Five