User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-108.3.134.219-20121201012843/@comment-74.134.149.69-20121204050009

My opinion?

I'm not saying that Nico is one of the seven of the prophecy, but I'd just like to point out: The Prophecy of Seven does not specifically call anyone the "Heroes of Olympus". Just because seven half-bloods answered the call, doesn't mean that there's only seven Heroes of Olympus - there could be more or even less than that, and Nico could be one of them. Another thing to point this out is a possible foreshadowing from The Last Olympian, where Hades says: "For today the House of Hades will be called the saviors of Olympus."

To keep on the subject of Nico, I think I heard somewhere that we'd see Bianca through Nico's memories during the series. This might be hinting at his own POV, but that could be turned about by way of Hazel's flashback abilities.

Reyna's not one of the seven, but again, just because she isn't one of the seven from the prophecy doesn't mean she's not a hero of olympus. I doubt that she'll have a POV, but if she did, it would probably take place during the Camp Jupiter vs. Camp Half-Blood battle. Even then, I doubt we'll see much of the battle until the last book - I believe there's still a month before it starts (but I only heard this on the audiobook, and I don't have the physical book to confirm this).