Mark James "Slave" Williams (born 1971) and Otis Frizzell (born 1971) are a New Zealand duo known as hip hop MCs and television and radio presenters. Together they are known for their musical work in the 1990s as MC OJ & Rhythm Slave and Joint Force, and their radio and television work in later years.As well as their work as a duo, each is known for his own achievements.