The Alliance, also known as the Grand Alliance, is one of two major political factions of the mortal races in Azeroth, its counterpart being the Horde which the Alliance has traditionally been at war with. Driven by tradition, the Alliance consists of powerful cultures and groups bound not by desperation or necessity, but by their deep commitments to abstract concepts like nobility, honor, faith, justice, and sacrifice. Striving to represent these high ideals, its many different peoples all contribute their technical, arcane, and spiritual wisdom toward the shared goal of preserving order on Azeroth and creating a peaceful and just world.
The memories of the allegiances and idealism of the Alliance of Lordaeron―centered in the homonymous continent―served as the ultimate inspiration for the new Alliance of the present day. The modern organization has the bulk of its forces on Northern Kalimdor and the south-eastern continents of Khaz Modan and Azeroth. Some of the members of the previous Alliance (such as Stormwind and Ironforge) are members of the Grand Alliance.
The Alliance has throughout the Warcraft story remained the only force that can match up to the Horde. These two factions have warred several times with their predecessors (Old Horde, Alliance of Lordaeron) having clashed together in the First, Second, and Third Wars. In the Fourth War, the last major conflict as of Battle for Azeroth, the controversial acts by the Horde Warchief Sylvanas Windrunner eventually caused a Horde rebellion led by Varok Saurfang. This led to a temporary unity between the two factions when Varok asked Anduin Wrynn, High King of the Alliance, for aid in assaulting Orgrimmar to end both the reign of Sylvanas and the enmity between the Horde and Alliance. Ultimately, the rebellion caused the Horde to lose its top leadership when Sylvanas killed Varok and abandoned the Horde. With his death and her abandonment, the Fourth War is considered over and the two factions have begun talks of peace, though many surmise it may not last or cannot forgive the atrocities of the past. Currently the Horde and Alliance is in an "uneasy armistice".
The Alliance is one of the two factions that player characters belong to―the Horde being the other―as determined by a given character's race (with the exception of Pandaren which can be both). Besides race, being a member of the Horde or Alliance affects gameplay through what settlements, NPCs, quests, reputation factions and in some cases items and encounters the player may access. Faction mechanics also prevent Horde and Alliance players from talking with each others or making groups together, and most PvP gameplay involves Horde players fighting against Alliance players. The divide between the Horde and Alliance—in regard to gameplay mechanics, story elements, and sometimes in social aspects like faction pride—acts as the core element of the World of Warcraft experience.
Alliance of Lordaeron
The Alliance of Lordaeron was the union of the seven human kingdoms, along with the dwarves of Khaz Modan (which also included the gnomes of Gnomeregan) and Aerie Peak, the high elves of Quel'Thalas, and others with major political influence including the Church of the Holy Light.
Aftermath of the second invasion
Events of the Third War led to an alliance with both the night elves, Alliance refugees, and the Horde. This alliance of Azeroth's defenders defeated the Burning Legion at the Battle of Mount Hyjal. While the night elves and Kalimdor Alliance, led by Theramore, became permanent, tensions began to erupt with the Horde. At the crux of the Third War, the corrupted scion of Lordaeron Prince Arthas Menethil laid the Alliance of Lordaeron to waste - beginning with the murder of his father and the annihilation of Lordaeron itself. He attacked Quel'Thalas shortly after, ransacking the elven homeland and nearly scouring the high elves from Azeroth. The survivors of this massacre proclaimed themselves blood elves in honor of their peoples' fall, and joined the Alliance resistance in Lordaeron prior to abandoning it due to racism on behalf of its commander. The Alliance resistance also fell apart after falling to treachery from Sylvanas Windrunner and her Forsaken.
World of Warcraft
With Lordaeron's fall and the devastation of the northern kingdoms, the rebuilt city of Stormwind became the new base of the Alliance, with the Ironforge dwarves becoming their staunchest and closest geographical allies. The gnomes of Gnomeregan had been unable to help in the Third War as they were dealing with their own issues closer to home — namely a trogg invasion of their city. Because an invasion of troggs paled in comparison to the might of the Scourge, the gnomes decided they would fight their war alone. In the end, they were forced to flee Gnomeregan and with their king, Gelbin Mekkatorque, settled in Ironforge with the dwarves as refugees. Indebted to their allies for their hospitality in their time of need, the gnomes again offered their services to the Alliance. The night elves, dealing with the loss of their immortality and having been exposed to the world outside their forests once more, decided they would have to make alliances with the wider world. Because of the animosity with the orcs for their continuing lumbering of Warsong Gulch, the night elves, in the end, joined the Alliance.
In the absence of his liege Prince Kael'thas Sunstrider, the regent of Quel'Thalas, Lor'themar Theron, looked into a number of potential alliances, though after failed renegotiations with the Alliance, opted not to rejoin it a third time—instead allying with the reformed Horde. A small number of high elves who did not become sin'dorei have chosen to rejoin the Alliance in recent times, with others never really having left in the first place. However, the night elves in particular took it upon themselves to warn their new Alliance allies of the high elves; the Highborne's part in bringing about the War of the Ancients figured heavily in the night elves' retelling of high elf history.
A few years later, the draenei joined the Alliance, partly due to their shared affinity for the Holy Light as well as animosity towards the orcs due to their history on Draenor. Stranded a world away from home, they are trying to establish a new base on Azeroth from the wreckage of the Exodar as well as gain the trust and cooperation of the Alliance. Not long afterward, Prophet Velen and his noble refugees played a key role in urging the Alliance to invade Outland and disrupt the Burning Legion's nefarious activities. Armed with their unshakable faith in the Light, the draenei ventured to their embattled former home as steadfast members of the Alliance and defeated their ancient demonic rivals.
The Alliance later assembled the Alliance Vanguard and won a costly war against the Lich King. Just prior to the Cataclysm, the gnomes' leader, High Tinker Gelbin Mekkatorque, led an attack on Gnomeregan’s invaders. It was a successful first maneuver, and the gnomes have managed to carve out a tenuous foothold in New Tinkertown, near the gates of Gnomeregan.
During the events of the Cataclysm, another race joined the ranks of the Alliance: the worgen of Gilneas (having previously left prior to the Third War). After the Cataclysm, the Greymane Wall was destroyed, allowing the Forsaken to attack and invade Gilneas unhindered. The Greymane worgen have been fighting the Forsaken in Gilneas and Silverpine Forest ever since, but most of their non-worgen citizens had to flee Gilneas to the safety of Darnassus. The night elves, who created the worgen curse that spread to Gilneas in the first place, felt obliged to help the Greymane worgen. They created a dwelling in Darnassus for them to seek refuge in as the war for their home rages on. Afterward, Gilneas was re-inducted into the Alliance.
While fending off Horde expansionism, the Alliance also sought to protect their scarred and broken world from utter devastation during the war against Deathwing.
Afterward, Theramore is destroyed by the Horde, and the leaders of the Alliance, outraged at this matter, completely devote themselves into the war against the Horde. Upon the parting of the mists of Pandaria and concurrent to the full-scale global escalation of the Alliance-Horde war, the Tushui Pandaren also joined, finding values among the Alliance races resonant with and similar to their own.
As tensions between the Horde and the Alliance exploded in Pandaria, King Varian Wrynn served as a mediator for the first time, tempering the cold tactics of war with an eye toward creating lasting peace. King Varian's leadership was tested as he successfully united the Alliance amid the pressures of war. The Horde, however, under the weight of Garrosh Hellscream’s command, continued to fracture. The trolls of the Darkspear tribe soon rebelled, and Orgrimmar was consequently placed on lockdown. Warchief Garrosh had sent crews into the Vale of Eternal Blossoms and into the Northern Barrens in search of resources to push his war machine forward. In the Vale of Eternal Blossoms, Garrosh seized the desiccated heart of an Old God to use as a tool of war, unleashing horrors upon the sacred valley, and consequently caused tensions to reach a boiling point. This culminated in the invasion of Orgrimmar with the help of a Horde rebellion. Varian's success solidified his position as high king, the commander of all Alliance forces.
Following the events of Siege of Orgrimmar, Garrosh Hellscream was imprisoned to be tried in Pandaria. Before the trial could conclude, aided by an ally who could manipulate the timelines, Garrosh escaped to Draenor of the past, and prevented the orcs from ever drinking the blood of Mannoroth, creating an untainted Iron Horde under the leadership of Grommash Hellscream. High King Varian Wrynn declared war on the Iron Horde and formed an Alliance expedition under the command of numerous talented commanders to face the orcish menace.
When the Burning Legion invaded the Broken Isles, King Varian personally led the Alliance's counterattack. The brutal fighting forced both the Alliance and the Horde to retreat, and Varian Wrynn sacrificed his life to allow his allies to escape.King Anduin Wrynn succeeded his father and was entrusted with the command of the Alliance's armies amidst the war against the Burning Legion.
Following the defeat of the Burning Legion during the Argus Campaign, the Alliance sought new allies to replenish their depleted ranks and bolster their forces in the event of future Horde aggression. Thanks to the efforts of Turalyon and Alleria Windrunner, the Alliance recruited both the Lightforged draenei and the void elves to their coalition.
Following the destruction of Teldrassil during the War of the Thorns, the Alliance and Horde entered a Fourth War against each other. Moira Thaurissan's efforts subsequently led to the formal induction of the Dark Iron clan, and in part due to Jaina Proudmoore's assistance, Kul Tiras also rejoined the Alliance shortly afterward, lending its formidable naval might to the Alliance cause.
The Alliance would eventually give aid to Varok Saurfang's revolutionaries with the goal of taking down Sylvanas Windrunner. However before fighting could start at Orgrimmar, Varok Saurfang, recognizing Sylvanas's loyalists as his brothers and sisters in the Horde and unwilling to spill more Horde blood, challenged Sylvanas to Mak'gora. During the duel, Saurfang was able to get Sylvanas to admit that she considered the Horde nothing, which caused the Warchief to swiftly kill him and abandoned the Horde altogether. In the aftermath of Saurfang's death and Sylvanas's betrayal, the Horde rallied together once more, with her former loyalists defecting to his revolution. Following these events, the Alliance and the Horde have entered into an armistice with one another.
Sometime later, the mechagnomes of Mechagon Island led by the recently-appointed Gelbin Mekkatorque joined the Alliance.