The Rakshas are led by Ravana, their king, and are the eternal enemies of Vishnu, one of the foremost divinities of the Hindu pantheon. They usually appear in the shape of a dog or a bird with a fat body, or as a skeleton.
The Rakshasas eventually ruled the forests and hated sages and seers who sought to bring the order of civilization into their realm. They would attack those seers and yogis who entered the forest to meditate and look for knowledge.
Tired of being persecuted by the Rakshasas, the sage Vishwamitra, sought the help of Dasharatha, king of Ayodhya, who sent his son Prince Rama to defend the sages.
As told in the Ramayana, Rama killed the Rakshasas and was praised by the sages. Later, Ravana abducted Rama’s beautiful wife Sita. In a great war, with the help of monkeys and bears of the forest, Rama defeated the Rakshasas, killed Ravana and brought peace to the forests.