User blog comment:SayuriDarling/Full first chapter of The Mark of Athena/@comment-115.146.161.162-20120607112414/@comment-117.193.41.225-20120607150521

But don't forget that Bellona is one of the Roman big three.

You have the Greek big three demigods : Percy(Poseidon/Neptune), Jason(Jupiter/Zeus), Hazel(Pluto/Hades).

From the Roman side you have Jason for Jupiter and Frank for mars. It is logical that Bellona's daughter should be there.

Also, the giant Enceladus - the anti-Athena has already been slayed. Isn't that a clue for why Annabeth can't be/needn't be the seventh?