User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-5774152-20130221034225/@comment-5929284-20130313085753

Plus, when it comes down to it, the only other Relationship Interest (with caps intended) is Percy & Annabeth, and many people aren't sure we'll get their point of view. I don't cont Piper and Jason, as their basically married, so it'd be good to have some interest p on the Argo II.

On the Nico front, I was straight up sure that it'd be one of the 7 who was left behind. But when you think about it, devastation is what happens in a war. And reading Markurions points, it would make sense for Nico to stay back, otherwise why introduce him to the ship now?