Diablo 3 Lore & Story Guide
Sanctuary, The Sin War, The Dark Exile, and the Horadrim
Having endured eons of endless conflict, a number of angels and demons eventually get sick of it. Led by the archangel Inarius, they use the Worldstone to create “Sanctuary,” a realm that allows the former adversaries to live together in harmony. Hiding it from their more combative brethren using the power of the Worldstone, Inarius and his followers inhabit Sanctuary and begin to breed, creating a powerful, mortal race of proto-humans known as the Nephalem.
The power of these beings triggers immediate beef. Inarius’ lover Lilith wants to use them as her personal army, and murders all the other angels and demons in Sanctuary with an eye towards taking control. Inarius, not liking this plan, banishes Lilith and uses the Worldstone to curtail the Nephalem’s supernatural powers, jealously guarding their allegiance for his own.
He soon has bigger problems, however. The secret of Sanctuary is eventually revealed to both the High Heavens and the Burning Hells, and each covet the Nephalem as a potential deciding factor in the Great Conflict. Rather than launch a full-scale invasion, the Burning Hells attempt to control the Nephalem through religious conversion. Mephisto’s son Lucion is dispatched to Sanctuary to found the “Triune Cult.” In response, Inarius creates the “Cathedral of Light,” which competes with the Triune for the devotion of the Nephalem.
Lilith, returning from exile, still wants the Nephalem for her own purposes, and manipulates a farmer named Uldyssian into leading a war against the Triune. This ploy backfires, however, and Uldyssian turns against Lilith and eventually against Inarius and the Cathedral of Light. After Inarius is defeated, the High Heavens and the Burning Hells negotiate a truce, which stipulates that they will not interfere in the affairs of Sanctuary.
The Prime Evils have a plan to circumvent the truce, as Evils tend to have. This is where it gets complicated — as if it isn’t complicated enough already — so pay attention. Working with Izual, a fallen Angel (who appears in Diablo II, Act IV), the Prime Evils learn of the Soulstones, objects of immense, Worldstone-derived power that are in the possession of the Angiris Council, the five-Angel oligarchy that controls the High Heavens. Izual explains how the Soulstones can be corrupted and used by the Prime Evils to destroy the boundaries between Sanctuary and the Burning Hells, effectively annexing the mortal realm.
Rather than steal the Soulstones directly, however, the Prime Evils employ a far more cunning plan, and engage in some epic, metaphysical possum-playing. First, they slack off in the Great Conflict, leading to an insurrection in the Burning Hells that pits the Lesser Evils Azmodan and Belial against Diablo, Mephisto, and Baal. The Prime Evils lose this war on purpose, and are banished to Sanctuary in their less powerful “spirit” forms — this is known as the Dark Exile.
Sensing an opportunity to strike a crushing blow in the Great Conflict, the Archangel Tyrael gives the Soulstones to the Horadrim, an order of mortal mages who eventually succeed in “imprisoning” the three Prime Evils within the Soulstones. What they don’t know, of course, is that the Prime Evils allow themselves to be captured on purpose, in order to corrupt the Soulstones from within. Deckard Cain, the player’s constant companion throughout all three games, is the last of the Horadric mages.
Diablo’s Soulstone is kept deep in the catacombs beneath Tristram Cathedral. Mephisto’s Soulstone resides in the east, in the Zakarum Temples of Kurast. Baal, in his hurry to corrupt his Soulstone, shatters it. To keep him contained (or so he thinks) Tal’Rasha, leader of the Horadrim, is sealed up with the Soulstone inside a tomb, to do battle with Baal for all eternity. Thinking itself safe, humanity’s history continues unaware for generations, while all the while, the Prime Evils continue to corrupt their soulstones, setting the stage for the events of Diablo I and II.