Mass Effect 3's multiplayer suite will be bolstered by a new enemy race and unlockables. The "Retaliation" DLC pack will be free to all Mass Effect 3 owners when it launches next week on October 9 - PS3 owners in Europe will have to wait an extra day, October 10.

Retaliation adds the Collectors as a new enemy faction to face off against and new unlockable kits: the Turian Havoc Soldier and Turian Ghost Infiltrator. You'll also be able to unlock new Collector weapons and outfit them with new upgrades, plus BioWare is adding new "hazard" versions of existing maps to Mass Effect 3's multiplayer - certain environmental dangers like sandstorms and lightning will now challenge players in addition to the enemy.

Finally, "Retaliation" adds a new challenge system to multiplayer, a database that chronicles your performance across multiplayer and awards "challenge points" for reaching certain milestones in multiplayer. Players can spend these "challenge points" on new titles and banners to customize their character profile.