User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-3146930-20121108002440/@comment-190.118.25.116-20121111221246

rick riordan said in his blog that nico sensed that percy and annabeth are alive and that we will see them in HoH so at least one of them will probably be narrating.here´s the blog post, it´s at the bottom of the page

here´s what i think will happen:

mabe one of them will have to sacrifice themselves to close the doors of death on the inside, mabe nico will have to prove he can be strong enough to do it in HoH and mabe that´s what percy´s big sacrifice will be. the sword of hades is a good hypothesis, especialy since the doors of death are in the House of Hades, so only a son of hades will be able to open them.

I think that the narrations will be: nico, hazel, percy and jason