We have the combined forces of Azeroth facing off against an Earth overrun by the forces of Hell as would be depicted in Doom 3 if they were successful.
For Azeroth the primary forces would of course compose both the Alliance and Horde along with the several neutral factions.
Both the Cyberdemon and Maledict will be present along with the other bosses from both Doom 3 and Resurrection of Evil. They will also possess the Artifact whereas Azeroth will lack access to the Soul Cube.
Who shall win?