Clad in standard Mk X Phobos armor, the light and fast Primaris Infiltrators are responsible for disrupting enemy communications and sabotaging targets of opportunity. The first that the enemy sees is a cascade of stifling smoke as the Infiltrators launch a flurry of smoke grenades, masking their advance. As the enemy scans the swirling cloud, the Space Marines drop their targets with disciplined bursts of fire, the snares of their sniper rifles lighting up each victim for the kill.