Uldyssian ul-Diomed was one of the re-emergent nephalem of the Edyrem, during the last days of the Sin War. His actions saved Sanctuary from being destroyed. 

He was once a simple farmer. Lilith awakened the sleeping power within him and gave him the strength to challenge the High Heavens and the Burning Hells.

Uldyssian channeled his energy to flood the Worldstone, resetting it, killing himself in the process. This act stripped the Edyrem of their powers. More notably, his sacrifice saved humanity, as the Angiris Council met to decide the fate of humankind. Moved by Uldyssian's act of self-sacrifice, Tyrael cast the deciding vote for humanity's continued existence instead of destroying it.

As the Edyrem's memories were removed as a condition of the pact made between Heaven and Hell to allow Sanctuary's continued existence, Uldyssian's actions were mostly forgotten, and it was believed that he had succumbed to a second plague.

Mendeln ul-Diomed, was the younger brother of Uldyssian. He would ultimately become a master Necromancer, an apprentice of the Guardian Dragon, Trag'Oul. He aided his brother in the defense of Sanctuary

After the Angiris Council decided to spare Sanctuary, Mendeln was the only one of the Edyrem to retain his memory—a side effect of his time with Rathma. Taking up the new name Kalan, Mendeln once again joined Rathma and Trag'Oul as a guardian of the Balance.

In the years that followed, Mendeln founded the Priests of Rathma, which would be known as "Necromancers." He began to teach others his skills and impart his understanding of the Balance, while recording said knowledge in the Books of Kalan. 

Rathma, whose birth name was Linarian, was a first-generation nephalem and tutor to the first Necromancer of his namesake's order, the Priests of Rathma. Rathma's parents were the ringleaders of Sanctuary's creation, Lilith and Inarius; he balked against their different yet equally domineering ways from an early age.

Rathma was a key participant in the Sin War, acting in the shadows alongside the mystical being Trag'Oul to sabotage both his parent's causes and preserve the Balance by ensuring that neither his parents nor their respective races could dominate the future of the world. Subsequently, he was one of the few residents of Sanctuary able to recall the events of the war, which was assumed to be an allowance for the original nephalem due to their highly advanced ages by that time. 

He then established the Priests of Rathma along with founding necromancer Kalan, ensuring the Balance would forevermore have its protectors even if the world could not remember the events that nearly destroyed it.

Bul-Kathos was born as part of the first generation of nephalem, in later times referred to as the Ancients. These nephalem wandered the world and adopted numerous philosophies as they spread across it.

During his reign, Bul-Kathos led his united clans to conquer vast territories and face numerous challenges. His armies clashed with savage beasts, hostile tribes, and even other civilizations. Through his military prowess and indomitable spirit, he carved out a mighty realm for the Barbarians.

However, as with all great empires, Bul-Kathos' reign eventually came to an end. The exact circumstances of his demise remain unknown, lost to the annals of history. But his spirit and legacy lived on among the Barbarians, who continued to revere him as the greatest of their kind.

The legacy of Bul-Kathos is a testament to the indomitable spirit of the Barbarians and their enduring warrior culture. His story serves as a reminder of the strength and unity that can be achieved even in the face of daunting challenges.

Fiacla-Géar was one of the Ancients; the first generation of nephalem in Sanctuary and brother of Bul'Kathos. Their bond was strong, and together they shared the secrets of The Ancients, of the mysteries below the peaks of Mt. Arreat, of the venerated task put to their people to protect those mysteries, and of the prophecies regarding the dark times ahead. They both agreed that, in order to fulfill their sacred trust, their people must devote themselves to nothing save that charge. 

However, they disagreed on exactly how the people could best do this. Bul-Kathos believed that only by bringing the tribes together and training them in strict martial discipline could the tribes faithfully concentrate on their goal for generations to come. Fiacla-Géar, on the other hand, believed that only through obtaining a spiritual oneness with the land they had sworn to protect could the people truly appreciate the importance of their role. 

Both agreed the other's philosophy had merit, and so around the time Bul-Kathos united the tribes, Fiacla-Géar gathered together a small group consisting of the tribes' greatest warrior-poets and shamans and mysteriously retreated into the forests surrounding the area known as Scosglen. There he and his people created the first of the Druid Colleges. 

Zoltun Kulle was one of the founders of the Horadrim, and the original guardian of the soulstones.

Kulle's thrist for power eventually corrupted him, turning the great mage to the side of darkness. After he created the Black Soulstone in his secret library, the Horadrim banded together to kill Kulle, putting his blood into jars and severing his head from his body in order to seal him. 

Kulle was among the Horadrim that bound their essence into vessels. As the Horadrim could not conquer death, these vessels would store their memories for future Horadrim.

Long after Kulle's death, Belial and Azmodan began to plot to overtake humanity. A group of Nephalem resurrected him and reconstructed the Black Soulstone with his help.

Deckard Cain was born into a long line of Horadrim, a secretive order of mages dedicated to fighting evil and preserving knowledge. 

Throughout his life, Cain dedicated himself to studying the lore and history of Sanctuary, gathering information on demons, monsters, and the ongoing battle against evil. Cain became an advisor and mentor to countless heroes who faced the threats of Diablo, the Lord of Terror, and other malevolent beings.

Tragically, Cain met his demise. While attempting to protect the Black Soulstone from falling into evil hands, he was killed by a group of cultists. 

Deckard Cain's legacy extends beyond his individual lifespan. His vast knowledge, teachings, and insights continue to shape the world of Sanctuary and inspire future generations of adventurers. He remains a revered figure, symbolizing wisdom, perseverance, and the unyielding fight against the forces of darkness.

Tal'Rasha was one of the most revered members of the Horadrim, and played a crucial role in the battle against the Three Prime Evils: Diablo, Mephisto, and Baal.

Tal'Rasha helped capture and bind the Prime Evils within soulstones. However, during the Dark Exile, the events that led to the Prime Evils' imprisonment, Tal'Rasha and his fellow Horadrim were compelled to make a great sacrifice. Tal'Rasha volunteered to serve as the host for Baal's soulstone, imprisoning the Lord of Destruction within his own body.

Despite the immense power and corruption of Baal, Tal'Rasha managed to retain his sanity and willpower for a time. He created a tomb beneath the desert sands of Lut Gholein to serve as his prison, ensuring that Baal's evil influence would be contained.

This tomb is eventually discovered and Tal'Rasha sacrifices what is left in an attempt to prevent Baal from returning to Sanctuary.

Adopted daughter of Deckard Cain, Leah becomes entangled in a prophecy that foretells the return of the Prime Evil, Diablo. When Deckard Cain comes into possession of a mysterious artifact called the Black Soulstone, which can trap and contain the essence of the Prime Evils, Leah accompanies him on his journey to seek answers and unlock its secrets.

Leah's role becomes increasingly significant throughout her journey. Her unique connection to Diablo allows her to hear his whispers and visions, providing valuable insights into his plans.

Ultimately, Diablo manipulates Leah's vulnerability and tempts her with promises of power and fulfillment. Consumed by Diablo's influence, Leah is transformed into the vessel for Diablo's rebirth as the Prime Evil.

Leah's story serves as a powerful reminder of the pervasive nature of evil and the personal sacrifices made in the battle against darkness. 

Lorath was present when the Horadrim attempted to seal the Black Soulstone under Tyrael's direction in the Tomb of Rakkis. When Malthael appeared to steal the soulstone and killed Lorath's comrades, Tyrael ordered him to flee and find the Nephalem who had defeated Diablo previously, which he obeyed as the former angel held off the Angel of Death long enough for Lorath to escape.

Lorath was eventually able to glean Malthael's location from Adria's scrying, discovering that he was in Pandemonium. Lorath remained behind to help the survivors in Westmarch as the Nephalem and Tyrael departed to face Malthael directly.

When Lilith returned to Sanctuary 50 years later, Lorath proved his worth again. He and a mysterious wanderer tracked her across the land and into Hell. Without him, she would never have been defeated.

Elias, a talented mage from Aranoch, was an apprentice to Lorath Nahr and part of the Horadrim. Concerned about the return of the Prime Evils, Elias delved into Horadric lore and discovered the potential of Lilith, daughter of Mephisto, to protect Sanctuary. 

He left the Horadrim when Lorath rejected his willingness to cross boundaries. Elias located the temple of Rathma, gaining power and learning about Lilith's opposition to Heaven and Hell. He formed a cult, unaware of Mephisto's manipulation, and successfully summoned Lilith with a failsafe of immortality. Elias accompanied Lilith, aiding her in corrupting places and preparing for their plans.

He was eventually put to rest by Lorath and his companions. His spirit is trapped forever in the tree of whispers, payment for the knowledge given to him.