Disruption Field (Su)

Prerequisite: Level 10

Effect: The construct emits a short-range field that disrupts magical energy. Creatures attempting to cast a spell while threatened by the companion take a -4 penalty to their concentration checks to cast defensively.

Resonance: The disruption field grows larger and more potent, but only briefly. Any creature within 30 feet that attempts to cast a spell (including the vanguard or the companion) must make a concentration check (DC 10 + the vanguard’s level + his Charisma modifier) or lose the spell. The field lasts for only 1 round.