Rez was a human male who at a young age was put in an escape pod that crash-landed on the planet Laylora. He met the Tenth Doctor and Rose Tyler when he was in his mid-teens. He was a skilled huntsman. After he defeated the Witiku, he went off with Petra Shulough and her crew. She acted as a mentor for him.
As a baby, Rez was put inside an escape pod which landed on the planet of Laylora. This upset Laylora's perfect ecosystem, causing earthquakes and the return of the Witiku. He grew up with a tribe of the planet, knowing nothing of his past besides the fact he arrived in an escape pod. After the defeat of the Witiku and Brother Hugan, Rez left the planet with Petra Shulough, restoring the planets ecosystem to its original, perfect state. (PROSE: The Price of Paradise [+]Colin Brake, BBC New Series Adventures (BBC Books, 2006).)