Chang was a 16th century Chinese novice monk.
He was one of the monks upon whom the Sontarans used their hypnotic technology. K9 recorded the trigger phrase which turned them into bloodthirsty killers. When Abbot Yueh Kuang spoke the phrase, K9 repeated it and broke the spell. However, Chang did not hear K9. He went into a berserk frenzy and killed all the Sontarans. (COMIC: Dragon's Claw)