Relic has announced that four-player online co-op is now available for the PC and PlayStation 3 versions of Warhammer 40,000: Space Marine.
The co-op is called Exterminatus Mode, a standalone Horde mode in which up to four players deal with invading Orks. Players earn points for completing challenges along with killing enemies. With the DLC comes two maps specially made for Exterminatus.
The Xbox 360 version will be coming soon, according to Relic, but no release date has been noted.