User blog comment:SayuriDarling/The Blood of Olympus Official Discussion/@comment-1820614-20141014181757/@comment-24065371-20141017220307

the other source for the power and focal point for belief in the gods was the acropolis they mentioned in the books, i suspect gaia was expected to rise there and the ground would be desecrated and thus the gods powers and influence

The roman and greek demigods were a tie to the world and the gods influence in the world as dinoysis said they need them, the giants/gaia intended for them to slaughter eachother and thus leave the gods with no legacy and no way to defeat them.T

Then gaia would mop the flaw with them

With the gods unable to stop the plan due to the giants and gaia's initiation of a war between the demigods splitting the gods personalities.