Rakshasas were often described as a subset of the asuras. Other subsets were yakshas and daityas. The word rakshasa came from the root raksh, meaning to guard. They may have originally been guardians, as one myth indicated that when Brahma created the waters, he created rakshasas to guard them. Individual rakshasas were often good but prone to getting cursed by the gods. Ravana was sufficiently evil to make up for any who were not. Their origin was variously explained as being created from the foot of Brahma, or from the paternity of one of two grandfathers (prajapatis)—Pulastya or Kasiyapa.
Rakshasas were given many epithets that suggest that heroes or incarnations would be needed to kill them: killers, offering thieves, cannibals, night- stalkers, blood-drinkers, and the like.