User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-170.235.245.53-20130604183722/@comment-24339098-20130604201114

The POVs aren't from the most powerful characters, It's the most important characters in the book. Rick Riordan said that Nico will have a large part in the book but he didn't say how large, most of us have just assumed that by large part Rick meant a POV.