User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-5593616-20130802214117/@comment-3146930-20130802214802

It wouldn't really be cool though, it would be sad; which isn't the same thing. The way I see it, any character from PJO have plot armor, as if something happened to them in HoO, it would make anything that happened in PJO seem meaningless. However, pretty much any character "introduced" in HoO has a chance of dying. My bets are on Frank, Reyna, or Octavian.