The nickname "D-Rock The Illest" was acquired in Derek's freshman year of high school. He played a talent show for his school in May 2009. The next day, two sophomores came up to him and called him "D-Rock The Illest" because of how he played at the talent show. Derek thought the nickname was catchy, so it has stuck with him since then.
Information taken from https://www.facebook.com/pages/D-Rock-The-Illest/194088707315919