The Quarian are from the planet Rannoch. The Quarians created the Geth as their robot servents but, the geth eventually overthrew the Quarians and the Quarians had to move t other planets or in fleets. Because the Quarian's home world had a unique atmosphere the Quarians were unable to go to other planets without wearing suits. The Quarians later had a series of wars with the Geth tring to take back their homeworld.
Quarians are generally a little shorter than humans. Thier lower legs are bowed backwards. Quarians have very weak immune systems.
Quarians have marines. Usually armed with rifles and also armed with shot guns and pistols. The Quarians also have a massive navy.
The quarians follow democratic laws while, a few squads of marines help enforce them. Admirals act as judges in the quarian govenments and three admirals are in every quarian court.