User blog comment:SayuriDarling/The Mark of Athena Official Discussion/@comment-4485028-20121007035731

I honestly hope that Gaea is either awoken around the end of the HoH (similar to Kronos) or near the beginning of the 5th book. I'll also accept nearly waking up and destroying everything but being stopped at the end of the 5th book. If she doesn't wake up or even get close to waking up, then it will kind of be disappointing for the series to have the main antagonist not as formidable as we once thought.

I've brought this up before, but honestly the Giants don't seem anywhere near as formidable as the Titans. Unlike the Titans (barring Krios, apparently, and Kronos being a special case), the Giants can be defeated and sent to Tartarus by demigods and gods working together. If that were the case with Titans, Atlas would have easily been defeated by Percy and Artemis. The best they could do was trap him again.

Also, the Giants are just much too cocky, and so far very few have actually displayed their own powers (Polybotes and the twins I believe). If the defeated ones don't come back later in the series, I feel the main villains would be much less of a threat than Camp Jupiter (except Gaea. Apparently, her waking up is very bad).