User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-10218971-20130603061220/@comment-10218971-20130603065637

They will need the Romans to help them fight Gaia. Also, if they don't stop them, they will destroy Camp Half-Blood.

But remember, demigods only came back to life because Thantos was trapped. ows hes free, monsters and mortals still die, but Gaia can control the doors and let bad mortals (Midas, Medea,etc) come back to life. And okay, you were right, the Doors of Death are in Greece.