User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-5927468-20130210134640

Any thoughts as to what gods or monsters might show up in HoH? Or are there any that you'd like to see? Given the title, I think it's likely that Hades/Pluto could show up. We know that Calypso is going to make an appearance in the series. And it's probably a safe bet that Percy and Annabeth will encounter a titan or two in Tartarus. But who else?

One scenario that I've had since SoN is that Lycaon and his wolves will show up again. Then Hazel will summon up a ton of silver to fight them with. Any other ideas?