kim nam-joon (; born september 12, 1994), better known as rm (formerly rap monster), is a south korean rapper, songwriter, and record producer. he is the leader of and a rapper in south korean boy group bts. he also sings his own songs. he has worked with artists such as wale, younha, warren g, gaeko, krizz kaliko, mfbty, fall out boy, primary, and lil nas x.