to sense their life force, which made it easier to sneak up on riders and kill them. Similar to insects, the Ra'zac have a three-staged life: first as eggs, then as humanoid youngsters and finally, after the first full moon of their twentieth year, they shed their skin and become huge beasts called the Lethrblaka. The Ra'zac are killed in the movie, but remain alive until Brisingr in the novels (although some Ra'zac eggs are later discovered in the final novel). Urgals – large, grey-skinned, horned humanoids. Although they are first considered beasts, Eragon later learns that the Urgals are as sentient and capable as humans, elves, or dwarves. Despite living in remote matriarchal mountain villages, the social rank and sexual attractiveness of males is determined by the number of foes they have vanquished, which leads to conflict with neighboring humans. They make a pact with Galbatorix to fight for him in exchange for more land sometime before the events of Eragon; when the king fails to deliver, they join the Varden. Urgals who grow to more than eight feet tall are considered 'Kull', and make up the Urgals' elite force of warriors. The Urgal race and the Kull were invented entirely by the author. Nar Garzhvog is a Kull warlord and brilliant strategist. He fights in the Battle of the Burning Plains and accompanies Eragon on a later journey to the foot of the Beor Mountains. Garzhvog hopes that, after Galbatorix's defeat, some kind of treaty and athletic contests can be established between the Urgals and humans to avert future conflict between their races. Yarbog is an Urgal who challenges the authority of Roran (his commander) during a mission. Roran defeats him in an unarmed combat wrestling match and earns his respect. Shades are humanoid sorcerers possessed by spirits. They wish to kill all other living things and can only be killed by stabbing them directly through the heart. They briefly are vanquished if they receive a normally mortal wound. Durza the shade, works for Galbatorix hunting down the new Rider Eragon and extracting information from Arya in the first book. He is killed by Eragon, but not before seriously wounding the Rider. Durza is portrayed by Robert Carlyle in the film Eragon. Varaug is the Shade created by three magicians using the body of a soldier during the siege on the city of Feinster in the third book.