You can only be an elite, nothing more just a spartan or an elite in halo reach.
Planet Reach being attacked by the covenant.
The Covenant invade Reach in the year 2552.
Well. . . Humans won, so Covenant sucks ^-^
Reach was a UNSC colony, and the last defense for earth. In Halo: Reach, the Covenant finds Reach and attacks it. The planet gets destroyed, and not 2 minutes after the UNSC ship Pillar of Autumn discovers Halo.
It is a prologue to the Halo series. It is about Covenant forces (the aliens) invading Reach (the planet) and destroying it and attempting to destroy the UNSC (humans).
Halo: Reach happens before Halo 3. The Elites haven't defected from the Covenant yet.
If You Mean change into elite, no, you can only do that in Halo 2, 3 and Halo Reach. But however you can use mods at halomods.com
Reach is lost. But..... Humanity is victorious after the events of halo 3 (the last in the series). The covenant leader is killed and the flood are exterminated.
you can in certain games, like multiplier, custom games and forge.
You can't. If you could, it would be in the "Covenant Vehicles" section.
Short answer: bad. In Halo: Reach the Elites (Sangheili) are fighting for the Covenant. This is rather confusing to many players 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.
Halo: Reach is the ending of the Halo games, it shows that the halo games were a story. It started with the first one, and they were all looking for the Halo which you find in the en of the game. There won't be anymore Halo games so that's why your spartan finally died in the ending and the Covenant was pushed off of planet Reach