The first step in this project was to define the world that Diablo: Unholy Alliance took place in. Obviously, we would be returning to Sanctuary - but what was the state of the world after the cataclysmic events of Diablo III, and what was the new threat for our heroes after the fall of the Lord of Terror? To answer these questions, I dug deep into the lore of the Diablo universe, looking for legendary events, unexplored locations, and compelling characters that could serve as the foundation for an epic adventure. I knew that Diablo needed to be central to this story, but I wanted to find a new and different way to present him to the player.
The final result was a document that defined the game’s setting, and the main story arc that would take guide players through this world. I also collected a lot of visual reference to communicate the game’s creative and emotional texture. This material would be the creative framework for the world building to come.
GAME SETTING
In the years after the fall of the Lord of Terror, chaos reigns over Sanctuary…
It has been more than a hundred years since the death of Deckard Cain, the defeat of the Archangel Malthael, and the fall of Diablo, Lord of Terror.
Since that time, Sanctuary has endured a century of chaos. The Zakarum Church, once a mighty bastion of faith, has devolved into a violent army of zealots intent on eradicating sin and ridding the world of darkness. Roving bands of the Children of Light scour the countryside in search of evil, ransacking villages, executing the unfaithful, and putting towns and villages to the torch. This second Zakarum Inquisition is even more bloody and violent than the first, with the ruling Que-Hagan, Maximillian II, vowing that Sanctuary would be cleansed once and for all in the blood of heretics.
The empire of Kehjistan has crumbled since the shocking revelation of Hakan II’s demonic possession by the Prime Evil Belial, and is now a fragmented patchwork of territories ruled by brutal warlords and their sellsword armies. The strongest of these, known as the True Sons of Rakkis, have laid siege to the capital city of Caldeum, where the remains of the empire’s nobility cling desperately to the ragged tatters of the old world.
The scattered barbarian tribes have been united under the banner of Korak the Shatterer, a powerful, half-mad chieftain who traces his lineage all the way from Bul-Kathos himself. Haunted by dark visions of a growing evil, Korak ordered the construction of a mighty fortress in the desolate hollow of Arreat Crater, it’s black, rune-wrought walls rising hundreds of feet into the air. Behind those walls the barbarians are raising a massive army, their forges burning day and night to create weapons, armor and engines of war. What Korak plans to do with this army is unknown, but such a powerful force has not been seen on Sanctuary since the days of the Sin War itself.
The mage clans of old, considered by many to be responsible for unleashing the powers of darkness upon Sanctuary, have been systematically hunted and eradicated by the Zakarum faithful. Once powerful in numbers and influence, they are now little more than pariahs who practice their ancient disciplines in secret, if at all. Rumors abound that the Vizjerei Clan has returned to the ruins of Viz-Jun to rebuild their once-great city, reviving their forbidden practices of demonic invocation and subjugation. There are even whispers that they have mixed their blood with that of demons, an unholy union that has spawned unspeakable abominations. Of those who have ventured to the ruins of Viz-Jun to seek the truth of these tales, none have returned.
With the passing of Deckard Cain, the last vestiges of Horadrim have disappeared from Sanctuary. As the power of the Zakarum church spread to every corner of the world, the legacy of the Horadrim became tainted by their fanatical doctrine. Instead of being remembered as Sanctuary’s staunchest defenders, the church portrayed the Horadrim as a mysterious, heretical cult with whose loyalties and alliances were unclear at best. Few are those who know the truth of what transpired in the past, and those who now seek the Horadrim’s knowledge do so at their own peril, often passing as mercenaries or relic hunters to escape the church’s wrath.
And beneath all of the chaos, something darker and more sinister has been growing like a cancerous tumor, an unnamed evil that spreads a long shadow across the land. Hellspawn have emerged from dark caves and ancient ruins, attacking towns and villages by night. The dead rise from their graves. Long-forgotten cults have resurfaced, profaning sacred places with vile rituals and human sacrifice.
Hopes are few, and heroes fewer. The Rogues have returned to their kin on the Skovos Isles. The Patriarchs of Ivgorod lay silent behind the walls of their mountain fortress, and the Umbaru have faded once again into the jungle mists. The Archangel Tyrael is dead, the hosts of the High Heavens are little more than myths and legends, and the Nephalem are no more.
It is an age in need of heroes - and these heroes must rise in order to face the growing darkness.
GAME STORY
When darkness falls, sometimes the only choice is a deal with the devil…
Against this backdrop of chaos, Gavilan Blackheart and the Reapers, an infamous band of relic hunters, have spent years searching the distant corners of Sanctuary for ancient wonders, feeding off the bloated corpse of the old world as it decays around them. Using an ancient and mysterious tome to lead the Reapers to long lost cities, ancient tombs, and powerful talismans, the Blackheart is a shrewd and battle-tested adventurer who makes a tidy profit selling his discoveries to the highest bidder.
But the Blackheart has a secret. His real name is Gavilan Cain, a long-lost descendant of Jered Cain, first of the Horadrim. Fearing retribution from the Zakarum Inquisition, Gavilan has always kept his true origins hidden away, secretly using the infamous book Book of Cain to learn the ancient ways of the Horadrim in order to find the relics of the past.
When the demoness Lilith, creator of Sanctuary and slaughterer of angels and demons, returns from her long imprisonment in the Abyss, the Blackheart is forced to face his destiny once and for all. Served by the demonic abominations known as the Harbingers, the Darkmother has come to exact her vengeance upon humanity for the eradication of the Nephalem, and she begins to carve a swath of death and destruction across the world.
Realizing that there are none left on Sanctuary that can stand against her power, the Blackheart is forced to make a desperate choice. Following a profane ritual described in the Book of Cain, Gavilan resurrects Leah, daughter of Adria and the Dark Wanderer, and Diablo, Lord of Terror, from the realms of death – and forges an unholy alliance with Diablo to fight against Lilith and the Harbingers before the world is consumed in blood and fire.
But there is cost to this devil’s bargain – and the Lord of Terror exacts a heavy price for his aid. As Blackheart, Leah and the Reapers journey to the four corners of Sanctuary to obtain the arcane talismans that Diablo requires, they will face unbelievable dangers at every turn – from soulless Zakarum Executioner squads on the moors of Scosglen, to the half-demon Magelords in the lost city of Viz-jun, to the Harbingers’ depraved blood bogs in the Southern Marshes. Through these horrors, Leah, visibly changed, proves herself to be a loyal companion to the Reapers – but her connection to the Lord of Terror is not so easily severed.
The story concludes in the ruins of Tristram Cathedral – where Lilith is defeated by the Reapers and Diablo in an epic battle which almost tears Sanctuary apart. In the aftermath of this conflict, Diablo betrays the Reapers, seizing the talismans of power and threatening to enslave all of Sanctuary - but Leah intervenes, resisting the urge to serve the Lord of Terror, and willingly sacrificing herself for her friends.
As Diablo prepares to kill her, the skies open up and a shaft of celestial light from the High Heavens engulfs Leah in holy fire. When the smoke clears, Leah has been transformed into the new Archangel of Justice, swearing upon her sword to protect Sanctuary for all of eternity. Diablo roars in anger, vowing that the Burning Hells will return to take their vengeance, and then disappears in an inferno of hellfire.
