Didn't really bother doing a lot of research on this movie. Is it from a book series?
I know it's a kid's movie (more like a teenager one), and I wasn't expecting Harry Potter or Lord of the Rings quality, but a few scenes can be done better. Overall, it also exceeded expectation -- I was afraid the dialogs will be overly cheesy, but that wasn't the case.
Couple things though:-
(1) The so-called "camp" thing that they stay at is pretty much an orphanage. Their human parents cannot get in there, their god parents aren't allow to see them. These are all abandoned kids!! Man, they'd all (most) have serious issues!
(2) Why are they training in martial arts with swords and shields?? There are no adults around, and since they cannot go into Olympia, the natural assumption will be they will rejoin the human society when they reach adulthood. Isn't there more important skills to learn than fighting with swords and shields, on their feet? :O Or are they all trained to be private investigators, military personnel (specifically special forces), bouncers, bounty hunters, stunt actors (?), etc?