User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-7153535-20130628164327/@comment-6064271-20130628212733

First of all Zeus, Poseidon and Hades are the big 3 because their children are the strongest demigods, not because everyone likes them. Remember nobody like hades but he is still considered part of the big 3. So just because the romans dont like neptune or pluto doesnt mean they are not part of the big 3.

Second, maybe the gods did the pact in their roman form but the roman demigods never knew about that and they never knew about the great prophecy. Also maybe they werent surprised to see alot of children of big 3 because they didnt care. They are divided in cohorts not by their godly parent. So with the romans its not who your godly parent is that gets you respect, its what you do in battle.