Alastor "Mad-Eye" Moody was a major character wich appears only in Year Four: Goblet of Fire, but had in fact an realy short appearance, beceause he was actualy a Death Eater, Barty Crouch Jr., wich used Polyjuice Potion to turn into Moody. He appears only when Albus Dumbledore freed him out of Crouch's chest.