According to Tamil classic Purananuru, Chera king Senkuttuvan conquered the lands between Kanyakumari and the Himalayas. Lacking worthy enemies, he besieged the sea by throwing his spear into it. According to the 17th century Malayalam work Keralolpathi, the lands of Kerala were recovered from the sea by the axe-wielding warrior sage Parasurama, the sixth avatar of Vishnu (hence, Kerala is also called Parasurama Kshetram (“The Land of Parasurama”)). Parasurama threw his axe across the sea, and the water receded as far as it reached. According to legend, this new area of land extended from Gokarna to Kanyakumari. The land which rose from sea was filled with salt and unsuitable for habitation; so Parasurama invoked the Snake King Vasuki, who spat holy poison and converted the soil into fertile lush green land. Out of respect, Vasuki and all snakes were appointed as protectors and guardians of the land. P. T. Srinivasa Iyengar theorised, that Senkuttuvan may have been inspired by the Parasurama legend, which was brought by early Aryan settlers.
Another much earlier Puranic character associated with Kerala is Mahabali, an Asura and a prototypical just king, who ruled the earth from Kerala. He won the war against the Devas, driving them into exile. The Devas pleaded before Lord Vishnu, who took his fifth incarnation as Vamana and pushed Mahabali down to Patala (the netherworld) to placate the Devas. There is a belief that, once a year during the Onam festival, Mahabali returns to Kerala. The Matsya Purana, among the oldest of the 18 Puranas, uses the Malaya Mountains of Kerala (and Tamil Nadu) as the setting for the story of Matsya, the first incarnation of Vishnu, and Manu, the first man and the king of the region.