Focus on one Chaos Marine at a time, since they can regenerate their armor like you. Sometimes, you can afford to focus Kraken Bolter shots on one until it goes down, but often there are several (with Renegade Militia support) and you have only seconds before you must dodge back behind cover. The easiest way to kill them is with headshots from the Lascannon; a single hit will kill them (if you miss the head, you'll need another shot to finish them off). Failing this, you can use grenades to take out their armor and then Execute to eliminate them quickly.
- Tactical: Effective at both range and melee. Use cover if engaged in ranged combat, or use stun attacks to interrupt their melee strikes. Roll away from their grenades, as they can deal tremendous amounts of damage.
- Havoc (Plasma Cannon): While their Plasma Cannon can rain fire from a great distance, it tends to be inaccurate and takes a while to fire another volley. Stay on the move, and attack during the cooldown period.
- Havoc (Lascannon): Their Lascannon possesses a laser sight, marking where they are aiming. Stay away from it, and attack once they have fired off a shot, as it has a long cooldown period.
- Champion: Deals massive amounts of melee damage and is hard to kill quickly due to its increased armor and health. Engage at range if possible. If they engage you in melee, roll or sprint away, or use stun attacks to interrupt. Note that activating Fury mode will allow you to instantly Execute them without requiring any prior damage or stunning!