Greek mythology doesn't necessarily care that much about good and evil, and the gods go back and forth between behaving and misbehaving all the time. Zeus raped women (see the story of Leda and the Swan for an example), which makes him a pretty unpleasant figure, and Hera threw away her own kid (Hephaestus) because she didn't like the way he looked. The gods are all capable of jealousy and mean-spirited behavior, which means they're certainly not the good guys.
But The Lost Hero is actually more of a superhero story than it is a Greek myth. So the Greek gods get cleaned up some (none of them rape their mortal lovers) and, even more importantly, the villainous monsters are turned into stereotypical super villains—complete with ranting, scheming, and declaring their intentions to take over the world. Evil is super evil in this book, so the good guys have to be extra good… even if the gods they are fighting for are sometimes a mixed bag.
Questions About Good vs. Evil
Is Piper tempted by evil when she thinks of betraying her friends? Or is she always good?
Is killing an evil creature evil? Does the novel ever ask this question?
Is Drew evil? Is Hera?
Chew on This
Evil in The Lost Hero is fun—the most entertaining characters are the evil ones.
The Lost Hero shows that you can be good even if you're not exactly fighting for good.