There will be player-made Alliances, albeit these will probably be little more than temporal ceasefires.
If you are asking if the game will have some form of "mark faction as friendly" during an event, then it would be possible (if the devs want to make a special event) but it won't be something that can be done permanently or at will. If you are asking if there can be a cease-fire and some form of collaboration between factions/clans, then the answer is yes. In PlanetSide2, on the Ceresserver, all the important NC clans learned to work together and collaborate. That collaboration later expanded to all the important clans from all three factions on the server. We hosted events where all the clans would spawn Galaxy ships (o the lag) and play air-bumper cars with them over the same base and we would even talk to one faction to gang up on the other faction. This game will be played the way the community decides to play it. Once the game comes out of beta and everybody knows what server they will be playing on, Clans will start to stick out, collaboration between clans will start to happens and there are no limits to what people on a server could do. If people wanted to work together and actually tried, we could get all four factions together in the same spot without anybody firing a round and all dance to the Thriller song together. Anything is possible. Best regards, WNxAkalonian
It is probably possible, idk about alliances between races i guess they can make it possible, but then again how far should it be allowed to go?
Hopefully not as it's pretty much Anathema for Chaos and the Imperium to work together. The Eldar would manipulate people and Orks just want to fight everyone.
If any race will become a bit too dominant/strong be 100% sure that there will be short time alliances between some of the other factions. Even if lore wise it would never happen...nobody wants to play a game where they get smacked around all day long.
Will we have some inter-faction in-game methods of communication other than spamming emotes at each other? And while Space Marines and Chaos would never admit cooperating, if their forces were threatened to be wiped by Orks, I can imagine they could negotiate cease fire, get rid of Orks, and continue their merry slaughter.
I personally hope that you can 'work together' as different factions in this game. I realize that lore would definitely take a backseat, but I would really love the option to play alongside my brother without having to be part of the same faction. If, for example, both the IG (my brother's favorite) and the Necrons (my favorite) were added as playable factions, I would like the ability to go out and work with my IG sibling. Questing together might be a little much, I get that, but if the Tyranids are going to be the common enemy NPC, I don't see any reason why a 'horde mode' gametype couldn't be added. Think "The Last Stand" from Dawn of War 2, my brother's IG Commissar, my Necron Lord, an Ork, Eldar, SM, and CSM can all join a game, and try to fight off an ever increasing wave of Nids. That would be perfect IMO.
ABHOR THE WITCH! KILL THE MUTANT! BURN THE HERETIC! NONE SHALL BE LEFT ALIVE! FOR THE EMPEROR! FOR ROGAL DORN! FOR SIGISMUND!