 Duke Kingston is King's twelve-year-old brother who is enrolled in the Landmark City School for the Gifted, of which he has the highest IQ.During King's wrestling coaching at his school with Axel, King was mothering Duke, asking him if he took his asthma medication and not letting him be a volunteer for some of King's moves.When King, Axel and Hawk left the school, Mr. Lee and the Mu-Team made their move.