The Mahabali legend in Kerala goes as follows: Bali was a just and the best king ruling the entire Malayalanadu. The very famous poem recited during the Onam festival states that during Mahabali (Maaveli, in slang Malayalam) all people were equals. All were happy, no cheating, no theft, no dishonesty at all. Maaveli wanted to become Indra and performed the rituals which would qualify him for that. The then reigning Indra was afraid and, he with the connivance of Vishnu, hatched the plot to dethrone Bali from the world itself. Sukracharya who was the Rajaguru of Bali (an asura) warned him when the dwarf brahmin came seeking "daan". Mahabali said whatever might happen, he would not violate the rules of the ritual which required that no brahmin is asked to go empty-handed. The daan becomes final only when the water is poured into the palm of the recipient, according to the sastras. So, Sukracharya took the form of an insect and blocked the snout of the "kindi" (a vessel used in old Kerala houses) from which Bali poured water. Vamana knew the trick and with a piece of hard "darbha" grass, poked the snout, thus making Sukracharya blind in one eye. Sukracharya, due to the pain, came out of the snout and the offer of daan was thus completed. Kerala people believe that the vanquished Mahabali asked for a boon from Vamana that he should be allowed to return to Kerala on the very day (Sravana star in the month of Simha) every year to see his beloved people. This day is celebrated all over Kerala as well as the Keralaite diaspora, irrespective of religion or caste. It is also the state festival. Historians and researchers hold the view that this is a memory of vedic aryan subjugation of native tribes in these parts of the country and the imposition of the caste system. There is also a view that this was an attempt, though milder and an initial one, to show that brahmins had the upper hand in a period during which there was intense fight for overlordship of the aryan community, between brahmins and kshatriyas. Since this initial resistance by brahmins did not bear sufficiently deasirable results for brahmins, the Parasurama legend came as the next one reflecting a phase in which brahmins became martial and vanquished kshatriyas, in the dim past. Subsequently, the kshatriyas and brahmins must have finalized a sort of ceasefire and mutual sharing of power; Rama signifies the same; a kshatriya being extolled as an avatar of Vishnu. There is also a yajurvedic stanza (I think) which means that the kshatriya is the best of God's creation and that is why, in a rajasuya sacrifice, even the brahmins sit at a level lower than the king's, or to the same sense. Later on, the need arose to pacify the vaisyas also from revolting and Krishna avatar was the legend which signifies that.