Oh yeah, it comes from all over. The problem I have with Riordan specifically is this idea that Greek mythology exists in a bubble and the fact he relies on mythological stereotypes instead of going back to the source material for new ideas.

(Seriously, Demeter and Aphrodite don't have strong powers? Look, I realize that the phrase 'I will destroy the seasons' hasn't invoked any kind of real terror since The Legend of Zelda: the Oracle of Seasons, but in a real-world setting, destroying the seasons is *devastating*. You don't need to have the children of Demeter sitting around growing sunflowers, and there's more to Aphrodite than simply vanity. There was a perfect, marvelous occasion to prove that love can be an amazing, strong force, a statement which was made in the book itself, and not only was it totally ignored, the statement itself was completely fucking useless to the main character!)

Sorry, I'm getting awfully wanky about children's books, but mythology in the modern times is a favourite trope, and these books were so utterly disappointing.