Kronos - a force so evil - he devoured his own children. Three of his sons escaped - Zeus, Hades and Poseidon. They destroyed Kronos - and banished his remains in the depths of Tartarus. But, Kronos is fated to rise again to exact his vengeance on Olympus and the world. Only one half blood child of the three eldest gods can defeat him - this child shall be our salvation - or the cause of our destruction.
(Source: ohpercy, via lostnico)