User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-122.164.246.114-20121221062619/@comment-3146930-20121221112222

Well Percy, Tyson, and Chrysaor are all children of Poseidon, so they don't count. Frank is a descendent of Poseidon as well, not Neptune. The only known children of Neptune we know of so far is Arion and Phineas