Hercules fights Kratos because he believes that Zeus favored him more and tries to kill Kratos to regain the status of Zeus' favorite and become the next God of War.Some of them may have been more heroic in the past before being corrupted by the evils of Pandora's box, but those whose crimes took place prior to the events of God of War 1 don't have that excuse. Adaptational Villainy: In real-life mythology, these heroes were praised for their adventures (despite having outdated values and behavior), but in the series, they are egotistical or somewhat corrupted in one way or another.
Poseidon doesn't mention Theseus' death when fighting Kratos but he does say that he will avenge Atlantis, and Hercules' death doesn't seem to concern Zeus in the slightest. Abusive Parents: Their parents (the gods) do not care much about them since they are openly callous about humanity and have caused many tragedies.
