User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-4485028-20130901011107/@comment-4485028-20130901131615

So I'm assuming that for the scenes in Tartarus, either one of the Roman demigods is going to be dreaming about them, or Annabeth would have a point of view (because Percy already has to and Annabeth only has one). If the latter is true, then each character would have 2 pov's before the last book comes out, paving the way for all 7 of them to have a point of view.