User blog comment:Equillibrium/The Elder Scrolls Online on PS4: Questions Answered/@comment-24635570-20140305002135/@comment-3124449-20140305031840

By "details" do you mean "lore"? The Aldmeri Dominion consists of the Altmer and the two races that cling on simply for protection (Khajit and Bosmer). As such, they have only two major goals: to achieve complete Elven dominance (extermination or subjugation of all Humans and Betmer) and to assure the influence of their favored deities, the Aedra. This puts the Altmer at odds with every other race of Tamriel, and they have only allied thenselves with Valenwood and Elseweyr for expansion and manpower. No one from another faction would EVER defect to them. The Ebonheart Pact includes the Nords, Argonians, and Dunmer. As they are all natural enemies, they knew that the only way to prevent their certain destruction would be to unite and defend their lands. This is especially true of the Dunmer. There is no real reason to join this faction from another, unless you were in the area when the war started and were forced to fight or be executed. The Daggerfall Covenant includes the Bretons, Orcs, and Redguards. Their only real motivations are to protect their lands and to work towards reinstating an empire to secure peace and free them are once again (they are led by the Bretons, after all). As they work mainly to create a lasting peace once more, this is really the only faction that an individual would have any reason to defect to.