The Alliance is one of the two major political factions of the mortal races in the world, its counterpart being the Horde.
The modern Alliance is the successor to the Alliance of Lordaeron, which was created at the behest of King Terenas Menethil II of Lordaeron and Lord Anduin Lothar of Stormwind following the First War, five years after the recokning. The human, dwarf, gnome and high elf races allied together to fight off the orcish Horde.
Events of the Third War, mainly manipulation by the redeemed prophet Medivh and the Battle of Hyjal led to an adhoc alliance with both the night elves and the Horde. The former became permanent, while the latter did not, as it was never ratified beyond the authority of Jaina Proudmoore who was not in communication with the main Alliance government at the time. Following the Third War, the majority of surviving high elves rebranded themselves as blood elves, who left the Alliance shortly after the war, following an attempted purge by Grand Marshall Garithos. A handful of high elves remain loyal to the new Alliance, most notably found in Theramore under Lady Jaina Proudmoore. Whereas in other places such the Hinterlands at the Quel'Danil Lodge, the high elves have retreated into isolation. Another sometime member of the alliance are the Wildhammer dwarves, but like the surving Quel'dorei for the most part they prefer to remain distant from core Alliance issues.
The Alliance is not a uniform governmental body, but is an alliance of mutual military and economic aid. In fact, with the destruction of Lordaeron and the ambassador council to the king, there is no unifying body to the Alliance itself, and no single speaker (or leader). There are not even any official, regulated, steady diplomatic ties - even thought all members of the Alliance keep ambassadors with the other races.
In the past, in the Alliance of Lordaeron, certain rules, customs and regulations were a constant across the entire union. However, with the fall of Lordearon such strict conventions have deteriorated, with only a simple bond of mutual protection and economic aid remaining.
Such factors make any cooperation sluggish, and considerably slows the rate at which the Alliance is able to reclaim its former lands and glory. However, the diplomatic ties are strong and in many ways, the Alliance is a rather uniform body in purpose, culture, and goals. All parts of the Alliance are steadfast in their desire to reclaim and rebuild, and all share a distrust against the Horde. According to the RPG books (Lands of Mystery and Lands of Conflict), today, about 300,000 souls belong to the allied races, across two continents.
Even now, as always, humans are the glue that stick the Alliance togther, being the most numerous and diplomatic race of the four species. Stormwind is the military, trade and cultural center of the Alliance. However, one must not be confused - the Stormwind boy-king is hardly the leader of the Alliance (like Terenas was to the old Alliance of Lordaeron).
Shortly after the fall of the human kingdoms and the destruction of the alliance, 20 years after the reckoning, the Night Elves joined the Alliance. Over five years later, the Draenei joins the Alliance by swearing fealty to King Magni Bronzebeard of the Dwarves.
The Draenei will join the ranks of the Alliance in the forthcoming expansion pack, the The Burning Crusade.
Other smaller powers are also part of the Grand Alliance:
- The besieged human defenders of Stromgarde.
- The Nethergarde Keep in the Blasted Lands, and it's force of Mages and Elves.
- The forces at Theramore Isle, led by Lady Jaina Proudmoore.
- The devastated city-state of Dalaran, which also controls territories in Silverpine Forest and Hillsbrad.
- The human nation of Kul Tiras, that does not appear in the game.
- A few small pockets of surviving High Elf|high elves, such as the Quel'Danil Lodge in the Hinterlands.