They are represented as enemies of the gods, and battle the gods, particularly Vishnu (see Rama). In the Ramayana, they are led by King Ravana and were believed to live on Lanka (cur: Sri Lanka). They are sometimes thought as being fat (or skeletal) dogs or birds.
The term is derived from an old Sanskrit root raksha which bears the meaning of protector and defender. Related words with these meanings are found in most modern Indian languages.
Alternative: Rakshasa, Rakshas