Young Jae Sung is a pre-made Sim from Midnight Hollow. He lives with his fellow bandmates Hyun-Moon Jun, Jin Sang Kim and Nadia Cho and is good friends with all of his bandmates. His name also suggests a Korean heritage, which is shared by two of his bandmates.
Young Jae is employed in the Music career as a Lyricist. He does not know anyone outside of his home aside from his boss. He has 5 points in the Guitarskill at the start of the game.