Warmweed was a drug used by the Skandians to make the slaves work harder and also is used by the head slavers to subdue the more rebellious of the slaves, as shown by Egon when he gets a slave to give the drug to Will after he is assigned to the Paddles, a torturous form of work. At one time Will was addicted to this drug but Evanlyn helped him through his addiction in Ranger's Apprentice book three (The Icebound Land). In The Icebound Land, it is revealed that Erak was against using warmweed on the slaves.