User blog comment:SayuriDarling/The Blood of Olympus Official Discussion/@comment-3464779-20141123185701/@comment-3464779-20141126120222

Percy's flaw is that he will have to face a choice between saving a friend or the greater good. (Like if the only way to kill Gaia is to have Leo sacrifice his life, then Percy wudnt let Leo die). Technically he didnt have much say in Leo's suicide attempt :P There wasn't an place for him to face his flaw :P