Ok. So how about this stunt? (Obviously this would be GM approval as well but just mechanics wise)
Know Thine Enemy: You have studied a particular creature in depth and know their attacks inside and out. You may use lore as either a mental or physical defense to a certain creature type. The type of defense must be specified upon taking this power.
explain how that would work with your character? storywise
Like for example, you play a Gun Nut, so you take a stunt that lets your Roll your Gun Skill instead of Scholarship when it comes to Gun based knowledge.
So your character is a Half Demon Half Angel
your character knows "Demons" he uses his Lore Knowledge of Demons to defend himself against "Fist" attacks from Demons? How?
Now MENTAL Attacks, I would buy.
I like the Stunt but I think it needs to be more specific.