Hades 2 confirms their villain with the youngest of the Titans and father of a few of the Olympic gods: Chronos. A being who ate his own children in order to maintain his stranglehold on his power.

Percy realizes that Kronos, the Titan and the father/grandfather of the Olympians, is likely the one conspiring against the gods. Hades tells them if that’s true, he wants to be prepared for war ...