Yoo Jae Hwan is a South Korean singer, songwriter, music producer, composer, lyricist and university professor. He has also performed as UL or as Heavenly Forest in the past. He graduated from Inha University College of Education Affiliated High School and later attended Inha University for a bachelor’s degree in Law. While attending university, he made his debut with the single album "I Didn’t Know Pain" and since then he’s been engaged in composing and producing music. He has helped produce and has provided lyrics for several of comedian Park Myung Soo’s songs. He first appeared on TV on the show "Infinite Challenge" but wasn’t able to do much as IU was also a guest and he had such a crush on her that couldn’t even look at her. He then appeared on "Superstar K 4" and made it to the third qualifying round before judge Lee Seung Cheul commented that he should focus on his studies instead of singing. That motivated him and he decided to join a composition team and began expanding from ballads and R&B to dance and EDM. Now, he appears on some talk shows but is very shy so he prefers to focus more on music.
(Source: Korean = Namu Wiki || Translation = MyDramaList)