Callous Casting

Requirements -

As a swift action, increase the DC of an instantaneous spell you cast this turn by 2 if you include any non-minion allies (including yourself) in its AoE.

If you have an ability to effectively not include allies in an AoE, then you do not get the bonus of this feat. If the ally is immune or resistant to the effect, then you do not get the bonus of this feat.