The Dawn
Before the birth of the universe, there was nothing, save a perfect pearl. In that pearl was Anu, a being made of shining diamond that was the sum of all things. Anu sought a state of total purity, and in order to attain, it cast all the evil aspects from himself. These evil aspects joined together, and out of them Tathamet, the Dragon, was created. Anu and Tathamet engaged in battle against each other for uncounted ages, neither gaining the upper hand.
After countless millennia, Anu and Tathamet each delivered their final blows, unleashing an explosion of light and matter which gave birth to the universe. In the center of the universe lay the Eye of Anu, the Worldstone. It was the foundation stone of all places and times, a nexus of realities and vast, untold possibility. From the remains of Anu and Tathamet, the High Heavens and the Burning Hells were formed. The seven heads of Tathamet spawned the three Prime Evils (Mephisto, Baal, and Diablo) and the four Lesser Evils (Azmodan, Belial, Duriel, and Andariel).
The Eternal Conflict
The Eternal Conflict is the unceasing war between the High Heavens and the Burning Hells. For ages uncounted, the High Heavens and the Burning Hells warred with each other, seeking control over the Heart of Creation, the Worldstone. Their battles most commonly occurred within the realm of Pandemonium, but at times went as deep as the Burnings Hells and as high as the Diamond Gates of the High Heavens. At some point, Tyrael ordered that a fortress be built around the Worldstone. Over the eons, control of the fortress changed hands many times. As a result, the Pandemonium Fortress took on traits of both the High Heavens and the Burnings Hells.
Having grown disillusioned with the Eternal Conflict, Inarius sought other like-minded angels and demons. Among them was Lilith, daughter of Mephisto. Together they succeeded in capturing the Worldstone and veiling it from Heaven and Hell. Inarius was then able to bind himself to the Worldstone and manipulate it to create a sanctuary for his fellow renegade angels and demons. Around the Worldstone, he created a huge mountain which contained and shielded it, creating the rest of his new world around this.
In their sanctuary, angels and demons conjugated, and out of their unions the Nephalem were born. These were the first generation of human beings, and they boasted impressive powers. Such were their powers that Inarius feared they might cause the High Heavens and the Burnings Hells to discover the location of their sanctuary. The knowledge that there would be no redemption for them should this happen, and that they, along with their world, would likely be destroyed for the abomination both Heaven and Hell would deem it, created a conflict as to what should be done about their offspring. Some wanted them destroyed, others wished to spare them. Inarius agreed to consider their fate, but Lilith wished to use them as a weapon to put an end to the Eternal Conflict, by taking over both the High Heavens and the Burning Hells. One night, she murdered every renegade angel and demon, certain that this would force Inarius to see things her way. Inarius was livid that his lover would betray him, but having promised long ago that he would never slay her nor let anyone else do so, he instead banished her to the void.
Inarius then altered the resonance of the Worldstone so that each successive generation of Nephalem would become less powerful than the last, until they no longer had any ability.
The Sin War
Around 4,000 years ago, a Vizjerei mage, Harash, discovered how to summon demons. This caused the Prime Evils to learn of Sanctuary's existence when the demon returned to Hell. Seeing the potential of humans, they set out to influence humankind and twist them to their cause, all without attracting the attention of the High Heavens. As such, they established the Triune, a religious order centered around the three guiding spirits — Bala, Dialon, and Mefis (actually Baal, Diablo, and Mephisto in disguise) — representing creation, determination and love. To oppose them, Inarius created the Cathedral of Light, a new religion based on tolerance, cooperation, and unity.
Around this time, Lilith was able to escape from the void, and in secret she altered the Worldstone to allow for the powers of the Nephalem to grow. She then wandered the world in disguise, looking for someone to suit her needs. In Uldyssian ul-Diomed, who was one of her direct descendants, she found the perfect target. She unlocked his Nephalem power and taught him how to use it, then convinced him to teach others how to do the same.
Wanted by both the Triune and the Cathedral of Light, Uldyssian travelled from town to town, showing the people that they didn't need either of the religious orders. However, Lilith was soon revealed to be a demon, and left only to return later under the guise of the Primus, leader of the Triune. Still under the attacks of the Triune, Uldyssian decided to confront them directly in Kehjan, where their main temple was located. To his surprise, many people followed him, wanting to learn more and develop their powers. With the help of Rathma, Uldyssian reached the Worldstone, where he did the impossible: physically altering it to cause their powers to grow. Along the way, Uldyssian and his followers destroyed every Triune temple and recruited as many people as they could. When Uldyssian finally reached Kehjan, he had a small army at his back. After defeating Lilith (who managed to survive, thanks to Inarius, though she was sent back to the void by him later) and laying waste to the Temple of Triune, Uldyssian turned his attention to the Cathedral of Light.
By now, Tyrael had discovered the existence of Sanctuary, and came to judge Inarius's crimes, though he had yet to inform the Angiris Council. Shortly thereafter, Uldyssian confronted Inarius. As Uldyssian severed the link between Inarius and the Worldstone, the armies of the High Heavens, on Tyrael's orders, tore through the sky and invaded Sanctuary. Then, to everyone's surprise and dismay, the ground opened up, and from it the armies of the Burning Hells emerged. Seeing angels and demons destroying his world as they fought, Uldyssian unleashed all the power he could in order to protect Sanctuary. He succeeded in pushing back the armies of the High Heavens and the Burning Hells, however, his power became too much to control and began to rip Sanctuary apart. With the help of Trag’Oul, Uldyssian shortly drew back all the energy he unleashed into himself and directed into the beyond where it wouldn't harm anything. And so it was that Uldyssian gave his life to protect Sanctuary.
After Uldyssian's sacrifice, the Angiris Council held a vote on the fate of Sanctuary. Imperius voted for its destruction. Malthael abstained. Auriel and Itherael voted for its survival. Tyrael, holding the deciding vote and deeply impressed by Uldyssian's actions, voted for Sanctuary's survival and ensured humanity's future. Another pact was made between the High Heavens and the Burning Hells such that neither side should interfere with Sanctuary. To seal the deal, Mephisto cast his mark on a point of Flux, preventing the Burning Hells from spreading their taint across Sanctuary, and in return Inarius was turned over to Mephisto.
Thus the Sin War ended.
The Mage Clan Wars
In the third century, two brothers rose to dominance from within the ranks of the Vizjerei clan of mages; their names were Horazon and Bartuc. Both were equally powerful and ambitious, and both were fascinated by the power one could obtain through the practice of Demonic Magics. However, the two differed in their views regarding how best to study demons. While Horazon viewed demons as a great source of power, he felt that in order to use that power best, one must harness a demon and bend it to one's will. His brother, on the other hand, grew to sympathize with the demonic powers and felt (with no small influence from the demons) that the demonic forces were best understood by allying with the Hellish authorities so their secrets could be shared freely. This was exactly what he did. These diametrically opposed philosophies caused a great schism that split the ranks and tore the Vizjerei clan apart.
The Vizjerei clan encountered the Umbaru tribes and used a few Umbaru clans from the Teganze jungle areas to create goatmen for their war effort. The plan was to induce demonic possession, and then transform them into savage goat-like creatures. This scheme backfired when five of those Umbaru clans turned against the Vizjerei. The Umbaru became obsessed with their desire to defeat the Vizjerei, and after decades of fighting, the warring Umbaru clans captured a Vizjerei sorcerer. This sorcerer helped them take control of all of the goatmen created thus far, then transformed the five warring Umbaru clans into goatmen themselves in order to defeat the mages. The demon Zagraal was somehow involved in this transformation, and after the war, the goatmen found themselves in servitude to the demon, killing and plundering in his name. This went on until the remaining Umbaru tribes sent their witch doctors to defeat Zagraal, who was the leader of the Khazra (a different tribe), from which that tribe drew their power, and the Umbaru Witch Doctors killed Zagraal.
Bartuc laid siege to Viz-jun, and was defeated by a group of Vizjerei led by his brother Horazon. When at last their fierce rivalry culminated in inevitable violence, the combatants learned too late that they had both been played as pawns by the demonic host. The ensuing battle was so great it set the very firmament aflame, and when it was complete and the stillness of remorse was all that remained, Bartuc lay dead, Horazon had created his Arcane Sanctuary and vanished into self-imposed exile, and the Vizjerei had learned a costly lesson. The small surviving group of sorcerers, the remnants of the once-great Vizjerei clan, resolved forevermore to spurn Demonic Magics and set about renewing their studies in the Elemental Magics. To further ensure that a similar tragedy could never happen again, they formed a secret order whose sole purpose was to police the mage clans, destroying corruption wherever they found it. This was the birth of the Viz-Jaq'taar, the Order of the Mage Slayers — otherwise known as the Assassins.
The Dark Exile
Predictably, the Prime Evils had no intention of fulfilling their end of the truce. However, they wanted to make it appear as if they did so that the angels, bound by their strict adherence to rules, would not interfere with their plans.
Here appears Izual, Tyrael's most trusted lieutenant. Perhaps it was Tyrael's change of stance about humanity that made him reconsider his own, leaving him open to the suggestions of the Prime Evils. Perhaps he simply felt betrayed by what he saw as an Arch-Angel putting human matters above their own. Ultimately, it is of little consequence. The important fact is that he went against Tyrael's orders and attacked the Hellforge. The attack was doomed to fail, and Izual was captured by the Prime Evils. He then turned over the secrets of the Soulstones and how to corrupt them to the Prime Evils and helped them plan their exile to Sanctuary. It is not known if Izual did this because he was corrupted by the Prime Evils, or if he wanted Sanctuary destroyed and thought giving it to the Prime Evils would be the best way to ensure that.
For the truce to hold, the Prime Evils couldn't directly intervene on Sanctuary. However, if they were exiled to it, weakened and bodiless, then the High Heavens might be fooled into thinking that the Lesser Evils overthrew them. So the Prime Evils stopped any action against the High Heavens, only focusing their attention on how they could take over Sanctuary. This infuriated the Lesser Evils greatly and in time, they instigated a civil war against Diablo and his brothers. And so it was that a great revolution, led by Azmodan and Belial, was set into motion as all of Hell went to war against the Three Brothers. Not wanting anyone to think they were playing into their hands, the Prime Evils annihilated a third of Hell’s legions before being banished to Sanctuary. Meanwhile, Azmodan and Belial began to argue over which of them held the higher authority. They took up arms against each other, starting a second civil war in the Burning Hells.
Now the Prime Evils were free to do what they wanted on Sanctuary without having to worry about the angels interfering, with the exception of Tyrael, who they knew would certainly interfere if he could. In fact, as long as the truce held, Tyrael was probably the only angel to pay any attention to Sanctuary. But the Prime Evils had planned for this. Izual had told them about the Soulstones, and how they could imprison them, but he also told them how to corrupt the Soulstones so that they could use them in their plan to take over Sanctuary.
The Binding of the Three
Tyrael, seeing the damage the Prime Evils caused on Sanctuary, recruited mages from across the land. He gave them the name Horadrim, and tasked them with imprisoning the Prime Evils within Soulstones. In Kehjistan, the order managed to capture Mephisto, and entrusted the Soulstone to the Zakarum, who hid it under a temple they built in Kurast. They then pursued the two remaining brothers across the Twin Seas. There they cornered Baal in Lut Gholein, waiting for him to venture in the deserts. When he did so, they pursued him. However, Baal's Soulstone was shattered in the resulting battle, and the Horadrim realized that even the largest remaining shard could not contain Baal for long. So it was that Tal Rasha, leader of the Horadrim, sacrificed himself to contain Baal. He was bound in an ancient tomb deep in the desert, held by unbreakable chains, to wrestle with the demon for eternity.
The remaining Horadrim pursued Diablo west into the distant lands of Khanduras, where a group led by Jered Cain finally were able to imprison him in his Soulstone. They hid this deep within a system of caves, then built catacombs and a small monastery on top of them.
And so with the Prime Evils trapped, peace came back to Sanctuary.
The Fall of the Horadrim & the Rise of Zakarum
After the Dark Exile, Zoltun Kulle returned to Kehjistan, where he became obsessed with creating a Soulstone of his own. His success resulted in the creation of a black Soulstone, and in somehow achieving immortality, before the other Horadrim were able to stop him. In a vain attempt to prevent him from going through with his plans, they decapitated him and hid his head deep in the eastern deserts. His body was sent into a pocket dimension, similar to Horazon's Arcane Sanctuary. It remains unknown how he created his Soulstone, but since those Tyrael gave to the Horadrim were shards from the Worldstone it's possible the black Soulstone was made the same way. However, this seems unlikely, as Zoltun never traveled to mount Arreat, and even if he had, he would have to have defeated the Ancient to gain entrance to the mountain. A more likely explanation is that he created it from the fragment of the Kiss of Mephisto left under the remains of the Temple of the Triune. It may also have been created on his own, perhaps using the smaller fragments of Baal's Soulstone.
Then, with no other evil to hunt and no directive from Tyrael, the Horadrim order slowly vanished. But while the Horadrim were fading away, the Zakarum religion rose to prominence. Before long, it became the most powerful organization in all of Kehjistan. The church then sought to colonize the western continent and spread their faith there. Rakkis was chosen to accomplish this task, and he successfully crossed the entire continent, ultimately settling in what is now called Westmarch. Following his success, many other lords were sent west to govern over those new lands.
The Return of Terror
One of these Lords was Leoric, who travelled to Khanduras and, in the name of Zakarum, declared himself King. On the suggestion of his trusted advisor, the Archbishop Lazarus, he made Tristram his new seat of power, and converted the abandoned Horadric monastery to a Zakarum cathedral. What nobody knew at the time is that Lazarus, once the custodian of Mephisto's Soulstone, had been thoroughly corrupted by it. In truth, Mephisto had directed Lazarus to head to Tristram with the objective of freeing his brother Diablo. In secret, Lazarus breached the deepest depth of the caves where Diablo's Soulstone rested and dispelled the wardings on it, thus awakening the Prime Evil.
Mephisto, his Soulstone having been closely guarded by the Zakarum, had been able corrupt his guardians, and in time took over the whole order. He even possessed Sankekur, who was the holy Que-Hegan and ultimate authority of the church. Although released from his prison, Mephisto couldn't leave the temple of Travincal without being exposed. Thus he set up a plan to have his brothers come to him instead. After being freed by Lazarus, his younger brother would travel east where he would release Baal from his prison; the two of them would then would travel together to him.
Once awakened, Diablo attempted to take over Leoric, but the King's will proved too much for the Prime Evil in his weakened state. For many months, Leoric fought Diablo's possession, which ultimately left him maddened and paranoid. In this state, Lazarus was able to convince the king that the neighbouring Kingdom of Westmarch was secretly planning to dethrone him and annex Khanduras. Angered, Leoric declared war on Westmarch and appointed Lachdanan to lead its armies. Ridding Tristram of anyone who could oppose Diablo, Lazarus sent Khanduras's meager army, as well as any "troublesome" individuals, away to fight a hopeless war in Westmarch. Among these was Leoric's eldest son, Prince Aidan.
Lazarus then secretly kidnapped Prince Albrecht, the youngest of Leoric's sons, and brought him down into the cathedral so Diablo could possess him. Many other children are taken that day, including Wirt, who was dragged into the labyrinth by the small demons. Leoric was furious over the disappearance of his son and accused the townsfolk of kidnapping Albrecht and ordered many of them to be executed. Meanwhile, Griswold ventured in the cathedral and rescued Wirt, but only after the foul beasts had begun to torture him. Then the remnants of Khanduras army, retreating after having been defeated, returned home to find the town of Tristram in shambles. Lachdanan, disconcerted by what he saw, confronted the king, who accused him of treason and ordered his guards to kill Lachdanan and his men. Having no other choice, Lachdanan killed his king, but as his sword pierced the heart of Leoric, the once noble king brought down a curse upon those who had betrayed him, vowing that they would serve him even in death. In their last attempt to honor their king, the knights brought Leoric body in his burial chamber to be entombed. However, as they did so Diablo raised Leoric as the Skeleton King, and the knights were overwhelmed by the curse with only Lachdanan able to escape it by venturing further down the cathedral. Lazarus, after having been missing since kidnapping Albrecht, returned and lured many of the remaining villagers down the cathedral under the guise of rescuing Prince Albrecht. Most of them never make it back up to the surface.
As the rumors of demons grew more common most of the townspeople fled Tristram. One exception was the witch Adria who had just traveled to Tristram and had a small hut constructed at the edge of town. Deckard Cain, the last of the Horadrim, spent many nights with her studding the ancient texts of the Horadrim, looking for the meaning of the recent events.
Events of Diablo and Diablo II
Aidan then returned to Tristram while the rumors of demons and treasure started attracting adventurers. Hearing the terrible things that had happened, he pledged to venture in the Cathedral and rescue his younger brother.
Aidan, helped by a rogue from the Sisterless Eye Rogues named Moreina and a Vizjerei mage named Jazreth, ventured down the cathedral, defeating the Butcher and the Skeleton King on the way. He also helped to free Lachdanan from his curse, and killed the Archbishop Lazarus. He then faced Diablo, and after an arduous battle defeated him. With a knife he removed Diablo's Soulstone causing the body to revert back to the dying form of prince Albrecht. Seeing the dead body of his beloved little brother shattered Aidan's mind that he fell to the whispers coming from the Soulstone, convincing him that he could contain the essence of Diablo and make something out of his hellish journey and the death of his brother. And thus, Aidan plunged the Soulstone in his forehead.
When he emerged from the Cathedral, Aidan remained distant, a secret burden weighing upon him. Troubled, he frequently visited Adria at night. One night he left Tristram, heading east. Gillian was tormented by horrific nightmares that seemed to be getting stronger. Shortly after, Adria and Gillian left for Westmarch where they would take a boat to reach Caldeum, Adria was pregnant with Leah at the time. She would later leave her daughter in the care of Gillian then take her leave, never to be heard from again.
Demons then attacked Tristram and burned it to the ground. Nobody was spared but Cain, who was caged and had to witness the townspeople being reanimated in grisly undeath and Griswold being corrupted into a demonic beast. Aidan, then referred as the Dark Wanderer, went through the gates of the Rogue Monastery, always spreading corruption in his wake, and in the mountains past the Eastern Gate he met Marius. Marius had fled from the corruption of the Rogue Citadel. He had ended up in what looks like an opium den where he tried to fight the nightmares off, already starting to go mad from the evil he witnessed in the Rogue Citadel. The Dark Wanderer found Marius, then seemed to lose control, summoning many demons, burning the establishment and killing any witness in the process. The Dark Wanderer beckoned Marius (it's not clear why, but the most probable explanation is that the Soulstone wardings prevented any demon from directly grabbing them, requiring the help of a mortal for that). Marius felt he had to follow him. From that moment, they traveled together east towards to the tomb of Tal Rasha. Behind them, Andariel, eager to regain the favor of Diablo, was left to block any pursuers. Continuing the corruption left behind by the Dark Wanderer, she conquered the Rogue Monastery and either brutally killed or corrupted many rogues, and as of the latter, Moreina was one of the corrupted ones and had her identity changed into Blood Raven.
The Dark Wanderer's activities attracted a group of adventurers to investigate the evils lurking behind him. These group of adventurers, consisting of a Westmarch Paladin trying to restore the Zakarum faith after its corruption by Mephisto named Carthas, a Barbarian from Harrogath; part of the Children of Bul-Kathos, their worshipped deity, a Necromancer of the Rathma cult trying to restore the scales of balance named Xul, a Zann-Esu Sorceress named Isendra, an Askarri Amazon named Cassia, a Viz'Jaq-taar Assassin and a shapeshifting Druid, banded together to cleanse the evil left behind by the Dark Wanderer. Their first stop was indeed the Rogue Monastery and their first task was to defeat Blood Raven and put Moreina's soul to rest.
Shortly after they rescued Cain from his cage in Tristram, then head to the Rogue Monastery where they defeated Andariel. They then travel to Lut Gholein with Warriv's caravan. After reaching the town, they began to search for Tal Rasha's tomb, hoping to find it before the Dark Wanderer could release Baal. Along the way, however, they stumbled upon an Arcane sanctuary where Jazreth stumbled upon after separating with Aidan, already slipping into madness thanks to their adventure. He became convinced that he could tame the demons in there, but it corrupted him, causing him to encounter the spirit of Horazon who proceeded to possess him, and thus he became known as The Summoner. The heroes defeated him, though while they wished him a peaceful rest, they knew that by tapping into dangerous magic, Jazreth more likely would be dragged off to Hell.
The Arcane Sanctuary indeed would lead them into the Tomb of Tal-Rasha, resuming their quest to stop Baal. But when they did they were already too late, and they found Duriel waiting for them. After defeating the Lesser Evil, they entered the chamber and found Tyrael imprisoned within it. Tyrael had tried to stop the Dark Wanderer from freeing Baal, but the bound demon had tricked Marius into releasing him. The two Prime Evils then imprisoned Tyrael in the tomb, left Duriel there to wait for the approaching heroes and set out for Kurast where they would reunite with Mephisto.
The heroes arrived to Kurast hot on the heels of Diablo and Baal, but were too late to stop the three Prime Evils from opening a portal to Pandemonium. When they reached the deepest level of the Zakarum temple, Baal had already left and Diablo had gone through the portal, planning to take the control of the Burning Hells back. Mephisto was left to guard the way, but the heroes managed the defeat him and, with his Soulstone, stepped through the portal.
The heroes found themselves in the Pandemonium Fortress, and from there reached the Burning Hells, soon finding Diablo and defeating him. They then took the two Soulstones and destroyed them at the Hellforge. And as Diablo's body reverted to that of the Dark Wanderer, they gave him a proper sendoff by wrapping his dead body in clothes and tossing it to the infernal sea of flames surrounding them.
By that time Baal had already found Marius. Tyrael had ordered him to go through the portal the Prime Evils had opened to then destroy the Soulstone, but Marius was left half insane when he saw the Dark Wanderer take the form of Diablo, and ended in a sanitarium in Westmarch. Baal approached Marius, tricking him into thinking he was Tyrael disguised (again, the Soulstone wardings could prevent Baal from taking the Soulstone by force, requiring it was given willingly). From Marius, Baal got his Soulstone back, and after burning the place down, he headed north towards Mount Arreat.
When the heroes left the Pandemonium Fortress and with the help of Tyrael traveled to Harrogath, Baal and his army had already began to march up the mountain. The elders of Harrogath had sacrificed themselves to erect a protective ward around the city, only Nihlathak survived. Nihlathak struck a deal with Baal: in exchange for Baal's mercy he gave him the Relic of the Ancients, an artifact that would allow Baal to enter Mount Arreat unchallenged by the Ancients. The heroes raced after him, on their way besting the ancients to gain access inside the mountain, but when they caught up with him, Baal had already fused his Soulstone with the Worldstone and began the process of corrupting it. They still defeated the Prime Evil then Tyrael appeared opening for them a portal to safety. Then Tyrael, seeing that the taint that had begun flow through the Worldstone could not be undone and fearing that this change would corrupt humanity and turn them over to the Burning Hells, hurled his sword at the Soulstone, shattering it and causing an enormous explosion that destroyed Baal's Soulstone as well as his own physical form, along with most of Mount Arreat.
The heroes managed to escape to safety thanks to Tyrael's portal. While the damage was done, and especially for the Barbarian who lost his home, they understand that it was necessary, and managed to keep their sanity in tact. They separated ways from there.
Prophecy of the End of the Days
...And, at the End of Days, Wisdom shall be lost
as Justice falls upon the world of men.
Valor shall turn to Wrath -
and all Hope will be swallowed by Despair.
Death, at last, shall spread its wings over all -
as Fate lies shattered forever.
These are the words of the Prophecy that will mark the end of the world, and ever since the destruction of Worldstone, the events has been set in motion. For some reason, Malthael grew increasingly disturbed with the destruction of Worldstone, to the point that he was often absent during the meetings of Angiris Council, until eventually disappearing altogether... Thus, marks the prophecy part of "Wisdom shall be lost"... as Malthael was the Aspect of Wisdom
Between Diablo II and Diablo III (including some tie-in stories)
Several years after the battle with the Prime Evils, the tales of the heroes are passed down throughout generations, with Xul mentoring a new set of next-generation Necromancers to ensure the balance is kept and Cassia, sensing that the darkness hasn't truly left the world, began training other Amazons in Skovos Isles to prepare for the upcoming battle.
Thanks to Tyrael's actions, Mount Arreat became corrupted and the terrain there became ruined and inhabitable, forcing the whole Barbarian tribe to become a more nomadic tribe, wandering to find worthy fights. Isendra found a young girl named Li-Ming and tutored her in magic, eventually moving together to the Vizjerei clan, but came in clash in the prospect of what their magic should be used, the two sorceresses preferred using them to help people even beyond the rules. However, when Isendra attempted to do that, she accidentally triggered a mass explosion that took the lives of many, and for that, the Viz'Jaq-taar sent an Assassin to punish her magic misconduct with death (it is unknown if it's the same Assassin that worked together with her beforehand). Isendra was killed and Li-Ming was too late to prevent that.
In the meantime, Carthas took the corpse of Sankekur, the body host of Mephisto, back home to Zakarum and formed a new Order of Paladins with the mission to safeguard the corpse of Sankekur which still radiated with Mephisto's evil influence. Slowly, he realized that Mephisto's influence was growing stronger and more corruptive, too much to handle for mortals like them, but he and his new Order of Paladins instead chose to seal themselves inside the burial grounds of Sankekur. As a result, he and his men succumbed into madness and killed each other, becoming undead knights, but this sacrifice prevented Mephisto's influence to spread any further.
Meanwhile, in Westmarch, demons started to ravage the land, and amongst the casualties were an innocent lady named Halissa and her whole family. Their deaths, especially Halissa's, unhinged the Sole Survivor of the family, Valla, who in turn developed extreme hatred towards any demons. For that end, she joined the Demon Hunters group and trained under the more experienced Demon Hunter Josen. Valla proved herself during the mission at Holbrook where she vanquished a demon corrupting a fellow hunter, Delios, making her one of the best Demon Hunters amongst the group.
20 years has passed since the Worldstone's destruction. At that point, the remaining Lesser Evils, Belial and Azmodan prepared to make their move to take over Sanctuary. While Azmodan laid low, Belial took form of the young emperor Hakan II, assuming the throne of Caldeum and manipulated the nation from the inside, causing suffering throughout men living there... Tyrael has since regained his Seraphic form, but in his absence, Imperius effectively took command of the High Heavens with Malthael's disappearance. Knowing that Belial and Azmodan were up to no good, Tyrael wanted to help the humans again, but Imperius strongly opposed to the idea. Disappointed with his insistence to follow the rules and not helping the innocents, Tyrael instead tore away his wings, rendering him mortal and he descended from the heavens... But unknown to Tyrael, this was yet another step to fulfill the Prophecy of the End of Days, the part "Justice falls upon the world of men."
Events of Diablo III
Cain tried to complete the Prophecy of the Ends Days and adopted Leah, she was 8 years old. Cain travelled with Leah to research the Neztem Petroglyphs, found on a natural pillar far out in the desert of Aranoch. Upon staring at this rock, Leah began having visions of a most violent nature. Cain and Leah arrived in New Tristram. 20 years after the destruction of the Worldstone, a fallen star crashed on the Tristram cathedral. The falling star attracted several group of heroes, one of the wandering Barbarians from Harrogath (same tribe, but not the same Barbarian in the previous quest), a Demon Hunter (most probably Valla volunteering for the part with the blessing of Josen, though it could be a male Demon Hunter as well), a spirit-hearing Umbra Witch Doctor, a Monk from Ivgorod, a Vizjerei Wizard (possibly Li-Ming, but could be a male Wizard instead) and lastly a Crusader from Zakarum trying to find a successor and just like Carthas before, trying to cleanse their religion from its corruption. These heroes entered New Tristram and tried to investigate about this falling star.
They first helped Leah rescue Cain from the Cathedral, with the crash awakening Leoric for the third and last time. They then defeated Leoric for good and retrieved a strange man that appears from the crater of the star. Trying to restore the man's memory, they tried to reforge his magic weapon, and found out that they are the Nephalems, but a witch named Maghda was also on the same goal. Maghda managed to outwit the heroes and attacked New Tristram in their advance, capturing the strange man and slaying Cain. The heroes rescued the man, who reveals himself as the now-mortal Tyrael. Resuming his mission, he drafted the Heroes to head to Caldeum and stop Belial, also Maghda's master. They also took Leah in after Cain's passing and she vowed to continue where he left off.
In Caldeum, while helping the locals, the Nephalem made it their mission to kill Maghda to avenge Cain first. They later found out from Leah that Adria survived and they rescued her from Belial's men. Adria revealed the existence of the Black Soulstone, which according to her, would rid the world of the Prime and Lesser Evils forever. To reform that, they have to take the remains of Zoltun Kulle and reforge his body, not just his spirit. While traveling with them, Zoltun Kulle kept goading the Nephalem to not trust their allies so far. When he is re-forged along with the Black Soulstone, Zoltun Kulle instead offers the Nephalem to rule the humans with him, as he can make them more powerful than Angels and Demons alike. His offer was refused and he's killed again. With the Black Soulstone at hand, the Nephalem assaulted Belial's hideout and defeated the Lord of Lies, sealing him into the Black Soulstone.
Leah later received a vision that Azmodan has amassed an army of demons attacking Bastion's Keep from Harrogath. The Nephalem and Tyrael headed there to defend the Keep, eventually working their ways off to confront and defeat Azmodan himself, sealing him to the Black Soulstone as well. Just when they thought everything was over, they were hit by a surprise that all along, Adria has been lying to them and jammed the completed Black Soulstone into Leah, reviving Diablo into her and enabling Diablo to resume his goal to take over High Heavens and winning the Eternal Conflict for the Demons side. However, true to his old hatred, for years, Imperius hasn't gotten a better opinion for humanity, possibly fulfilling a part of the Prophecy of the End Days: "Valor shall turn to Wrath.", thus he remained antagonistic to the Nephalem even as they're technically helping the Heavens.
The Nephalems followed Diablo to Heavens along with Tyrael, and was surprised to see it in complete mess and a lot has been put through despair as during the early assault, Diablo sapped away the hope by imprisoning the aspect of hope itself, Auriel and set in the Lord of Despair, Rakanoth, to guard her, thus fulfilling another part of the Prophecy: "all Hope will be swallowed by Despair." The Nephalems also learned from Itherael that because they were not included in the prophecy, they could change the outcome and prevent the fall of High Heaven. They rescued Auriel, defying the part of the Prophecy, and moved forward to confront Diablo, who has merged with the other evils and becomes Tathamet reborn. After escaping his Realm of Terror, they defeated Diablo, but they know for sure that the battle isn't over... true evil never dies after all. And another thing, unlike Aidan and Albrecht, Leah's body remained missing even after Diablo was defeated...
Reaper of Souls
Not wanting the evils within the Black Soulstone to taint the High Heavens, Tyrael decided to hide it in Sanctuary again, with a new group of Horadrim. However, just as he's finished hiding it, Malthael returned from his disappearance, now as an Angel of Death, he has other plans, he wants to eliminate all the demonic source from the world, including humans', so evil will disappear forever and the Angels win the Eternal Conflict. Tyrael managed to contact the Nephalem to help him stop Malthael and they regrouped in Westmarch, which is under the assault of Malthael's reapers and is very close to become a dead city. And so, another part of the Prophecy was in motion: "Death, at last, shall spread its wings over all."
Helping the people stave off Malthael's forces, the Nephalem managed to slay one of his lieutenants, Urzael, and they caught wind on where Adria was located. Filled with vengeance over what she did to Leah, the Nephalem became quite eager to slay her, restraining themselves to extract information first before doing the deed. Thankfully for them, they met Adria conjuring the image of Pandemonium Fortress where the Black Soulstone, therefore Malthael, is located, exactly the information they needed before they killed Adria, who transformed into a demon.
With the information at hand, they headed to High Heavens, and was surprised that Malthael's Reapers were attacking other Angels, much to the surprise of even Imperius. Imperius couldn't find it to strike against his brother, so he assigned the job to put Malthael's madness to end to the Nephalem's hand, though he had no intentions of making peace. After taking the Siege Runes to the battering ram, they broke through the fortress, and to stand a chance against Death (Malthael) himself, they released the souls located within the Soul Well. With those at hand, they confronted Malthael, but in process of battle, Malthael destroyed the Black Soulstone and absorbed the essence of Prime Evils. But even that wasn't enough to defeat the Nephalem, and with his previous act of destroying the Black Soulstone, his death set the essence of the Prime Evils, Diablo included, free.
With Malthael defeated, humanity is safe once more. It was then Tyrael realized one thing... the Nephalem became too powerful that champions of both Hell and Heaven were no match for them. But one particular detail remain: They are still mortals, and so, they're susceptible to be tempted to evil. He only hoped that the Nephalem will have enough willpower to the temptation of evil, they could save or doom mankind either way...
Between Diablo III and Diablo IV
Malthael's campaign against humanity nearly drove mankind to extinction. The sheer loss of life and slow recovery has halted the gradual ascension of man back into the Nephalem. The High Heavens, having suffered heavy casualties themselves between Diablo and Malthael, have closed their gates to Sanctuary entirely. The Great Evils have freed themselves from their merger with Diablo and are recovering in Hell until they can act once more.
Rathma, the first child of Inarius and Lilith, has several visions of the future. Consulting with the great serpent, he transcribes his visions into a prophecy:
Inarius, free from Hell and returned to Sanctuary, recreates the Church of Light and restructures it to worship him as humanity's savior. Learning of Rathma's prophecy, Inarius has incorporated it into Church scripture as prophesizing how he will kill Lilith and be welcomed back into the High Heavens.
The Pale Man, desperate to save Sanctuary from further destruction in the Eternal Conflict, lures a scholar and two treasure hunters into an underground ruin and uses them as a sacrifice in a ritual to summon Lilith from the Void.
Events of Diablo IV
Fifty years after Malthael's defeat, a Wanderer lost in a storm happens upon the small village Nevsek looking for shelter. The villagers tell the Wanderer of demons and evil lurking in the ruins below, which the Wanderer slays to protect Nevsek. The Wanderer is celebrated as a hero, but during the celebration they are drugged by the villagers, who had been corrupted by the influence of Lilith. They feed the Wanderer Lilith's blood in a ritual to sacrifice them, but a priest of the Church of Light rescues them.
The blood gives the Wanderer a link to Lilith, granting them visions of her activities in Sanctuary. The priest sends the Wanderer to find Lorath Nahr, the last of the Horadrum, who's knowledge of demons may help them stop Lilith's ambitions. Finding the hermit, he and the Wanderer travel together to the Church of Light. Once they make it to the major city, Lorath leaves on his own to track down the Pale Man, leaving the Wanderer to tell the Church of Light about Lilith's return.
