I wouldn't be surprised. Sometimes there's a lot of similarities in various mythos, especially as people try to explain the world around them. But... ours aren't myths in the sense that they're fake stories, even if most mortals think they are.

[ she pauses, because she doesn't miss his tone, and she doesn't even blame him. ] Like, I've been to the Underworld. It's definitely real in my world.

[ even before tartarus - somehow her very first quest ended with her, percy, and grover at the throne of hades himself. ]

I remember. You wouldn't tell me what it was. [ not entirely true so much as he felt it difficult to describe. ] Are they friendly?