Percy , refusing godhood for himself , forces the gods to swear on the River Styx that they will recognize all of their children by the time they turn 13 and that they will end the pact of the Big Three , in which Zeus , Poseidon and Hades were barred from fathering demigod offspring . Percy , refusing godhood for himself , forces the gods to swear on the River Styx that they will recognize all of their children by the time they turn 13 , honor the minor gods , and free innocent titans ( most of which are the enemies of the major gods ) .