User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-72.95.198.214-20130626142326/@comment-6064271-20130626234109

in the great prophecy the hero wasnt Percy it was Luke. The line a single choice shall end his days means that Percys choice to give the cursed blade to Luke so then Luke could stab himself in his "achilles heel" which was in his armpit since he was the only one who knew where his achilles heel was. So the choice Percy made to give him the blade ended his (Luke's) days.