Clad in Mk X Phobos-pattern armour, the light and fast-moving Primaris Infiltrators are responsible for disrupting enemy communications and sabotaging targets of opportunity. The first the enemy sees is a cascade of choking smog as the Infiltrators hurl a barrage of smoke grenades, masking their advance. As the foe peers into the swirling cloud, the Space Marines bring their targets down with disciplined bursts of fire, the augur-scopes of their marksman bolt carbines lighting each victim up for the kill.