Chang was a 16th century Chinese novice monk.
He was one of the monks upon whom the Sontarans used their hypnotic technology. K-9 recorded the trigger phrase which turned them into bloodthirsty killers. When Abbot Yueh Kuang spoke the phrase, K-9 repeated it and broke the spell. However, Chang did not hear K-9. He went into a berserk frenzy and killed all the Sontarans. (COMIC: Dragon's Claw)