User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-1515612-20130221033240/@comment-3146930-20130224051927

I know! In The Son of Neptune, Percy and Frank have this ling talk about how Roman demigods leave camp to train in the Greek style. I really thought there was some third camp of demigods somewhere, but there is still time to prove my theory right.