The Demon Boyz were a British hip hop group formed in London by Demon D, Mike J and DJ Devastate. They began rapping whilst in their early teens, performing at the Rebel MC’s Beat Freak gigs. Their big break came when they won a competition on Dave Pearce’s rap show, their prize being to perform live on stage with Derek B, Faze One and T La Rock at a gig at Camden Palace.

Derek B – aka Derek Boland, quasi-A&R man for Music of Life records – was so impressed with the group that he put them in touch with the company’s founder, Simon Harris.The group recorded the song "This is a Jam" for the inaugural release from the label’s classic Hard as Hell series, Hard as Hell (Music of Life, 1987), and the group were quickly signed up on the back of this song’s reception.

As one of the first groups to rap in their natural accents – in an era when most British rappers were adopting fake American accents to emulate the hip hop music they were listening to – the Demon Boyz created a stir, and laid the foundations for the creation of a truly original UK scene.

Three singles and the landmark album Recognition (Music of Life, 1989)& heavily featured on music of Life's album "Hustlers Convention" considered by many to be rap's first ever live album followed, and the success of the former brought the group to the attention of Island Records’ subsidiary Mango Records.

The group moved to the label, releasing the single "International Karate" (Mango, 1990) to high acclaim. However, Island closed their subsidiary soon afterwards, and the group found themselves without a record deal.

Going back to their roots, they joined Tribal Bass, the record company run by their old friend Rebel MC. Feeling much more at home, the group released two more singles and their second album, Original Guidance (The Second Chapter) (Tribal Bass, 1992).

The album was well received within the scene, earning an even higher regard than their first release, but shortly afterwards the group split.Mike J reappeared later on, under the name Million Dan guesting on the single "High Grade" (Knowledge and Wisdom Records, 2001) by Knowledge and Wisdom, and then with the single "No Replica" (Against the Grain, 2003) and working with DJ Skitz on "Dogz and Sledgez" from the album Homegrown (Vol 1) (React, 2004).

He continues to record, although his forthcoming album Spektrum has been delayed.