Sundered Defenses

Artillerist Technique: 7th level Your precise bombardments make even the most hardened defenses crumble. When you cast a power that calls for a tech attack or a Dexterity saving throw, it reduces partial cover by one step (from three-quarters to half or half to one-quarter) against creatures affected by it. If an affected creature has one-quarter cover, your power ignores it entirely.

Granted by Artillerist Technique at 7th level.