The Warhammer 40K Universe have psychics (kind of like DFRPG wizards), but also the opposite - psychic nulls. Depending upon their power level, psychic powers and effects just don't work on them and things near them. They have negatives (e.g., they creep people out).
If I wanted to craft a template for a Magic Null, how might I tackle that? I don't want to make them too powerful, but I'm not sure what powers to give them. There are counterspells, which are kind of like this, but I imagine their powers as more "always on."
As always, any thoughts are appreciated.