The Convenant.
Because they -the Elites- are taking over Reach, and you are trying to stop them. This is rather confusing to many people as they were allied with the UNSC in previous Halo games, but keep in mind that Halo: Reach is set before even the first Halo game, Halo: Combat Evolved.
No, firefight was not introduced until Halo ODST which was made after Halo 3. Only Halo ODST and Reach currently support it. Halo 4 will have a new game type called Spartan Ops which is similar.
Yes, but you need to do it over xbox live.
Halo reach is older
no, Masterchief is not in Halo: Reach. Halo: Reach is set before the discovery of Halo, if you have or Know about the Halo book: The Fall of Reach, it is a closer view of the plant reach. but there are some other Spartans in it!
after Halo reach,there is no more In total, there is :Halo 1,Halo 2, Halo 3, Halo ODST, Halo wars and Halo reach
There are no skulls in Halo Reach.
halo reach is the bomb
No, Halo Reach shows what happened before Halo 1. In fact, in one of the missions in halo reach, you can see Master chief
halo,halo 2,halo 3,halo3 ODST,halo wars,halo reach
chances are no their will not be a new halo after reach
No, there is no Hayabusa armor in Halo Reach.