Hades is Zeus's Brother. Zeus is the father of Kratos. Kratos is the nephew of Hades.
that said... hes related to Athena too... since Hades makes a reference to Kratos aciidentally killing Athena as "you killed my Niece"
That said, if you want a family tree. Pandora. the almost adopted Daughter Kratos tried desperately to save --- PSN~ MilliardoPcraft PSASBR Mains: Zeus/Kat/G.Cole/E.Cole Official Crash Bandicoot/Hades of the PSASBR Board.