User blog comment:Darkcloud1111/Fantasy Fellowship and the Adventure Dream Team/@comment-4485028-20120915144026/@comment-3498371-20120915160458

We do have confirmation about who the 7th half-blood is. It's Annabeth, as stated in the DD. But apart from that, I think you're right. Noone who hasn't read the series has ever heard of Hazel, Frank or any character apart from Annabeth and Percy.