Second Dark Exile

The Second Dark Exile refers to the banishment of the Prime Evils to Sanctuary by the Lesser Evils millennia after the original Dark Exile. This article also covers the Hunt for the Three Prime Evils on Sanctuary by the Three Factions, though most sources treat this as a separate event.

Background
The Second Dark Exile had its origins in the aftermath of the Great War, after God and the original Satans perished. The Prime Evils, having seen the Three Factions become weakened from endless years of fighting, turned their attention to their goal of the perversion of human souls, for they knew that mankind was key to their eventual victory over the High Heavens. With the Three Factions weakened and exhausted form fighting and God having died, humanity was left undefended. This deviation from the norm caused many of the Lesser Evils to question the authority of the Three, and so brought about a great rift between the Prime Evils and their servitors.

In their ignorance, the Lesser Evils began to believe that the Three were afraid to continue the war with the High Heavens. They considered themselves innately superior to humankind, and that the Eternal Conflict was theirs alone to fight. Frustrated by the cessation of the war, Azmodan and Belial saw the situation as their chance to overthrow the Prime Evils and take control of the Burning Hells for themselves. Belial manipulated Azmodan into revolt and the demon lords made pacts with their brethren, assuring them that humanity would not deter them from seizing victory in the Eternal Conflict. Andariel and Duriel had their doubts at first, afraid that they would fall in the coming conflict. Belial however, kept them in the fold. Azmodan and Belial devised a plan to end the stalemate, achieve victory in the Sin War and ultimately ride the bloody crest of the Great Conflict straight into the very arms of Armageddon. Thus, a great revolution was set into motion as all of Hell went to war against the Three Brothers.

The Uprising and Aftermath
Hell became embroiled in civil war as the Prime Evils were turned upon. To their credit, the Prime Evils fought with devastating power, annihilating a third of Hell's treacherous legions. In the end, however, they were overcome by the traitors Azmodan and Belial. The Prime Evils, weakened and bodiless, were banished to the mortal realm where Azmodan hoped that they would remain trapped forever. Azmodan believed that with the Three set loose upon humanity, the High Heavens would be forced to turn their focus upon the mortal plane, thus leaving the Gates of Heaven abandoned and defenseless. Those few demons who still pledged allegiance to the Three Brothers fled the wrath of Azmodan and Belial, escaping to Sanctuary to seek out their lost masters.

As the fires of war died down, Azmodan and Belial began to argue over which of them held the higher authority. The pact that they had made quickly fell to ashes as the two demon lords took up arms against each other. The legions of Hell that remained were polarized behind either warlord, launching themselves into a second civil war. One account states that there was no falling out however, and that the two Lesser Evils began a scheme to subjugate all life to their will. In truth however, the two lords did indeed do battle up until at least the Darkening of Tristram, by which point Azmodan had held the upper hand for quite some time. Eventually, both Lesser Evils would turn their attention to Sanctuary.

In truth, the Primes' banishment to the mortal realm had been masterminded by the Primes' themselves. With the Three Factions weakened, the Prime Evils would spread their taint throughout Sanctuary, corrupting mankind and subjugating the nephalem. However, they could not have foreseen the Three Factions working together and hunting them down.

The Hunt for the Three
The coming of the Three marked a time of evil in the history of Sanctuary unlike any other. The cataclysm that followed their arrival brought immense change to the world when the Three unleashed their hellish followers upon the world. These followers wrought great destruction upon the lands of Sanctuary. That which was not consumed by the arrival of this malevolence was often twisted and altered by the effects of the resulting chaotic forces. Many of the native creatures inhabiting the world became vile and depraved shadows of their natural forms. A world that once allowed the unfettered development and expansion of mankind became a place where only the strongest could survive.

The Prime Evils roamed the east of Sanctuary, feeding upon the lusts of men, leaving chaos in their wake. Entire nations were led into brutal and petty wars. Their exile from Hell had left the Three with an insatiable hunger to bring suffering and pain to all who would not kneel before them, and so the Three Brothers ravaged the lands of the Far East. The Three could inhabit the bodies of humans, and used this ability to control political and religious figures, allowing them to deceive mankind easily and corrupt the faithful. This went on for untold centuries.

Eventually the presence of the Primes was discovered by Tyrael, Archangel of Justice. Knowing that the Angiris Council had spared mankind by a single vote at the end of the Sin War, the Elder Angel dared not inform his brethren that Hell threatened to corrupt humanity once again. Somehow, he had to intervene without alerting Heaven to the situation. To this end, he met with the leaders from the Three Factions, the Four Great Satans, Azazel, and the Archangel Michael. Having told them everything regarding the Prime Evils, Tyrael gave them three soulstones, each a shard of the now destroyed Worldstone. Each of these soulstones would be used to contain the essence of a single Prime Evil. The soulstones allowed the Three Factions to track the Primes, even when their true forms were hidden within mortal shells.

The Binding of Hatred
The power of the soulstones proved to be much more difficult to employ when used against the great Prime Evils. Voraciously disposed to possessing hapless mortals, the Three Brothers found that they were immune to the effects of the stones while occupying human souls. Thus, the Three Factions were forced to kill the innocent victims of the Three so that their demonic essences could be subjected to the soulstones.

During the hunt for Mephisto, the Lord of Hatred frequently made use of undead minions, and common soldiers were hard pressed to combat the seemingly endless tides of undead that he summoned. During the assault on the demon's Fortress of Bone, the army the Three Factions led was nearly overwhelmed by these beings, but were able to nullify the demon's ability to resurrect soldiers through a type of magic and won the day. After five years, the Three Factions located Mephisto in or around one of the urban centers of Kehjistan. They succeeded in capturing and imprisoning the demon, but the fight cost many innocent lives. The Three Factions thus vowed to avoid confronting another Prime Evil in a populated area.

The Three Factions also had to decide what to do with Mephisto's soulstone. But Azazel convinced them to capture the other two Prime Evils and then decide what to do with the soulstones. Thus the hunt continued.

The Binding of Destruction
In time, Diablo and Baal journeyed across the Twin Seas to the deserts of Aranoch, the Three Factions in close pursuit. 58 days after the hunt had begun, Baal took refuge in the city of Lut Gholein. Michael had believed that Baal had been headed north for Scosglen, but regardless, for three days, the Three Factions waited patiently. The demon then fled into the scorched wasteland, but the harsh desert offered no solace from his persuers. Turning to fight, Baal unleashed his powers against the Three Factions, as the very ground itself gave way, and the combatants fell into a network of subterranean caverns. And yet, the Three Factions still pressed the attack. It is here, that accounts vary. One states that in a desperate attempt to survive, Baal hurled a devastating spell against Tal Rasha, shattering the Amber Soulstone. However, it was not enough, and the raging demon lord was subdued. Tal Rasha, gathering the largest of the stone's shards, trapped Baal's destructive essence within it.

Accounts differ, as to whether it was the suggestion of Michael or Azazel that a powerful member of the Three Factions would act as a surrogate soulstone, using the shard as a conduit to their body. The angel Raphael, one of the Four Great Seraphs and Michael's brother, volunteered for the role, fated to wrestle with the demon for eternity. It was here that Tyrael appeared once more, telling Raphael that his sacrifice would be remembered. He then led the men through the tunnels into the burial chambers of long-dead kings. In one of the largest tombs, the Three Factions built a binding stone, etched with runes of containment, held fast to the chamber's walls by unbreakable chains. Michael ordered his brethren chain Raphael to the stone, after which Tyrael jammed the soulstone into his chest, leaving him to wrestle with Baal's spirit for eternity. Sorrowfully, the Three Factions sealed the chamber and departed.

The Binding of Terror
In the wake of Raphael's sacrifice, the Three Factions continued their hunt for the last Prime Evil, Diablo. They began searching for the Lord of Terror, in a hunt that would take them the better part of a decade. Finally, in the year 1019, fifteen years after their quest had begun, they found the Lord of Terror in the lands of Khanduras. In a battle that nearly cost the Three Factions their lives, Diablo was defeated, and his spirit imprisoned.

Tyrael then appeared before the Three Factions a final time, commending them for their victory. He ordered that the soulstones containing the demon lords must be guarded at all times. Thus it was decided between the leaders of the Three Factions that each race would take a soulstone and guard, keeping its existence and true nature hidden from the populace. The Angels would watch over Raphael's tomb that held Baal's spirit, Mephisto's soulstone would be granted to the Fallen Angels, and Diablo's to the Devils.

The hunt was over.

Legacy
Michael established guards over Raphael's hidden tomb, now lost to the desert sands of the Sahara and hidden away from all save for the Angels. He then named Metatron as Raphael's successor to be the Clubs for the Four Great Seraphs.

The Fallen Angels, with Mephisto's soulstone, constructed a labyrinth prison complex to contain Mephisto's soulstone and placed a plethora of guards to watch over it. Kokabiel acted as the warden to Mephisto. While the act of construction drew many Fallen Angels to take up such a sacred duty, Mephisto's presence would have disastrous consequences for the religion in later centuries.

When the Devils returned to the Underworld with Diablo's soulstone, they decided that one family alone should not be entrusted with guarding the stone. So the soulstone would be entrusted to a deciding noble family every year to be guarded. Every year, a new family would be chosen by the Four Great Satans to take the soulstone and guard it. The true nature of the soulstone was kept a secret exclusive to the Four Great Satans so as to not spread fear among the nobility, creating a lie that the stone was merely a symbol of the end of the Great War.

Though the hunt was finally over, Michael, Azazel, and the Four Great Satans knew that the Prime Evils would eventually returned and seek to continue their goal of destruction. Thus they had to prepare for the inevitable.

Centuries later, the Three Factions' fear was well founded, as each of the Primes returned to wreak havoc on the mortal world. Mephisto was able to corrupt the Grigori from within, subverting their guardianship over his soulstone. A small civil war was waged over the Fallen Angels, with the incorruptible Fallen Angels defeated as Azazel ordered them to go into hiding and cut off all contact from one another to prevent being discovered. Mephisto assumed control over the Grigori through Kokabiel and enacted a hunt for Fallen Angel loyalists.

Kokabiel soon freed Baal under Mephisto's orders, still wearing the guise of Raphael as his powers increased thanks to his host. Unfortunately, Baal had not returned totally unscathed: while he indeed had expected to be freed by a servant of his brother, the transfer of his demonic spirit into the body of an Angel of the Lower Heavens was barely successful. The body which the Lord of Destruction settled in, wasn't enough as it was not able to contain the immense power Baal possessed and began to decay as a result. Over time, his body was unable to move on its own, and he took on a ghoulish, undead appearance with missing appendages. Baal knew that the forgotten Tomb of Tal Rasha had the power and devices needed to sustain him, with the decay of his body slowed by the ancient Binding Stone that bound him so long ago. Thus after killing Kokabiel and retrieving his soulstone, Baal ventured to the Tomb and bound himself there, soon calling for Aidan Kain in dreams and waking nightmares to come and take his soul into his Sacred Gear

Diablo returned in the event of Riser Phenex's engagement to Rias Gremory, possessing the body of Aidan Kain. Diablo then fled to Tristram, utilizing the Cathedral as his base of operations where he would once again enact his reign of terror. Unfortunately, he was pursued and defeated by Rias Gremory and her Peerage, along with Sona Sitri and her Peerage, who came to rescue Aidan from the demon lord's possession.