At 12th level, you gain a number of extra attacks of opportunity equal to your Dexterity modifier (minimum 1). You can use these attacks of opportunity only against spellcasters in your threatened area who cast or attempt to cast defensively. The Spellbreaker feat, the caster's bane bloodrage power (see below), or some similar effect is still required to make attacks of opportunity against spellcasters who are casting defensively. You have this benefit constantly, even while not bloodraging.
