User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-5210020-20121026002310/@comment-5112532-20121026191408

It seems that in the 4th book, all the Roman demigods (Jason, Frank and Hazel) will get a POV. In The Mark of Athena, there were four so hopefully there will be four in The House of Hades!

RR said that Thalia wouldn't have a part in the Mark of Athena, and since the Argo II is already in the Mediterrean Sea, I doubt if she (and the hunters) would join them in Rome or Greece. Unless, she joins the battle at Camp Half Blood but I think that if anyone should narrate whats happening in America, it should be Reyna.