If a Character has the Fiend Slayer as a Follower ("If you encounter a space with instructions to draw one of more Adventure Cards, you must draw one more card than requires") and then the Prophesy Adenture Card is played (which has the same instructions), on a space where the Character would draw one card, would he draw two extra cards?
As I read it, I would say that similiar to Monk not being able to use the Psionic Blast spell, that they would only draw only one extra Adventure Card but I'm not 100% sure.