User blog comment:Loreofwings/The Seven/@comment-67.234.10.37-20120505212240/@comment-3146930-20120505214035

There is already a son of Hades/Pluto, so two Underworld demigods seems kind of weird. As far as a child of Athena/Minerva, that is the most likely as she is the last of the Olympian Week gods. If it is Annabeth, that has yet to be seen