You can now choose your side in the coming conflict:
Space Marines, Imperial Guard, Inquisition, Eldar, and Tau - Click Here
Chaos Space Marines, Chaos Daemons, Traitor Guard, Necrons, Dark Eldar, Tyranids and Orks - Click Here
You can use any number of armies you wish for this campaign, but you must choose a side (see above). Once your side is chosen, you cannot change it during the course of the campaign.