Rap Monster was born on September 12, 1994, in Ilsan, South Korea and has one younger sister. Before his debut with BTS, he was an underground rapper under the stage name "Runch Randa". He released a number of tracks and once collaborated with fellow underground rapper Zico. He is part of the underground Korean hip hop crew called Daenamhyup, consisting of the members Marvel J, l11ven, Supreme Boi, Iron, Kyum2, Kidoh, Samsoon, Illipse and DJ Snatch. The group has been active since 2009. Rap Monster is known for his intelligence. He achieved an 850 on the TOEIC when he was in junior high.[4] He was part of the top 1.3% of the nation in the preparatory university entrance exams for language, math, foreign language and social studies, and has an IQ of 148.[5] Alongside his native language Korean, he is also fluent in English.