(One of the chapters to get updated every now and then)
Each faction within the UA have a specific role in the defence of the Alliance with the most famous and major being:
Autobots: the Autobots purpose are mostly armor support and make up about 60% of the Alliance armored forces meaning if the crew is killed the vehicle can still fight on.
Rebel Alliance: Famous for it's pilots, the rebels provide 70% of the UA's air support
Mobile suit corps: the MSC provide their mobile suits as infantry support both in space and on the ground
The M.I, G.A.R, I.G, Terran Dominion UNSC, Unggoy each playing a major role in the alliance infantry forces
Space Marines, ODST, Spartans, Sangheili, Protoss, Avengers, Jaeger Program, Overwatch/Blackwatch, S.H.I.E.L.D: forming the backbone of the special forces, these factions are to be feared and respected