Theoretically, any faction can team up with another, as long as you have a good enough reason. Technically, Necrons and Chaos are enemies, so they would never 'team up', per se, but one could create a feasible story in which they both work to exterminate the Imperium. They wouldn't be working 'together' (because Necrons would kill any living thing--including Chaos Marines--on sight) but they would have the same goal.
Technically you can play any army against any army, and any army with any army, except where rules specifically state that you may not (E.g. Black Templars may never ally with an army containing pyschers) It would however be extremely unusual, but so long as you have a good background story, it should be fine.
The Space Wolves are Space Marines.The Space Marines are a genetically enhanced race of human beings and the Space Wolves are a chapter of these Space Marines.If you want to team up Space Wolves with another chapter of Space Marines, for example, Ultramarines, or Black Templars, you would have to check in the codex to see the rules that apply for allied armies.
the answer is undoughtably tyranids but that's about all thy are good at. but the enemy doesnt get much of a chance to shoot at them because tyranids have lots of abilitys that make them go very fast towards their food.
In 40k Space Marines In fantasy Orcs and Goblins This is only an estimation. I cannot guarentee correctness. Frogapple
Yes, there are U.S. Marines in the campaign and as a team in multiplayer.
XenosNecronsTau EmpireEldarTyranidsOrksDark EldarImperiumImperial GuardSpace Marines-Dark Angels-Black Templar-Blood AngelsDaemonhuntersWitch HuntersChaosChaos Space MarinesTraitor GuardChaos Daemons
Chaos
There are approximately 5 Recon Marines active. Err
Well, Space Marines and Chaos Marines are the main ones. Space Marines get different types, by their specialty. Assault Marines specialize in hand to hand combat. Devastator Marines specialize in heavy weapons, etc.
Mine is Chaos
Police they are better trained, also the swat team is more trained than marines!
Philip the hedgehog is one of the topest strongest fastest hedgehog in the world and no hedgehog are stronger then Philip the hedgehog Philip the hedgehog used to be a hero and now he's evil Philip the hedgehog work's alone after team chaos kick him off the team and with his ultimate powers like the force,speed,faint attack, poision dart, and such as his chaos power like chaos blast,chaos control, chaos punch,chaos kick, chaos hiperthomia,chaos altmussfear.