Mahabali (IAST: Mahābalī, Devanagari: महाबली, Malayalam: മാവേലി, മഹാബലി, Tamil: மாவேலி) also known as Bali or Māveli was a benevolent Asura King, and the grandson of Prahlada in Indian mythology. The festival of Onam, celebrated by the people of Kerala, India and the Government of Kerala declared Onam as the ‘State Festival’ of Kerala in 1960, commemorates his yearly homecoming after being sent down to the underworld Sutala by Vamana, the fifth avatar of Vishnu.
Read more about Mahabali: Conquest of The Universe and Banishment, Genesis of Onam, Views On Bali