Do you think Percy Jackson and Harry Poter have the same fatal flaw?

I mean, think about it. In both books, both characters would do anything for their loved ones. Harry saved Ginny, Sirius, Ron, and Mr. Weasley. Percy saved his mom, Grover, Annabeth. Harry blamed himself for Sirius's death. Percy blamed himself for Beckendorf's death. So doesn't it sound like both Harry and Percy's fatal flaw is personal loyalty?