User blog comment:Menara/Bianca di Angelo may be one of the 7/@comment-3459279-20110909234958/@comment-3146930-20110910010544

Demigods are the offspring of a god and human, not a god and other. Percy even mentions it to Annabeth at one point that the prophecy could be talking about a monster or something, she says that half-blood always refers to Demigods, as in human/god hybrids