Angels of Darkness, Soldiers of Light

Angels of Darkness, Soldiers of Light is the title of a proposed Diablo novel by Robert B. Marks. Marks wrote a full outline, but it has never been published and as such, should not be taken as official Diablo lore.

Overview
Angels of Darkness, Soldiers of Light opens around twenty years after the events in Demonsbane. Sarnakyle, Siggard's companion in the e-book and later the wizard who turns the Vizjerei clans back to elemental magic, is asked to perform an exorcism. The exorcism goes poorly; one of the wizards is killed, but just before the demon is sent back to Hell, it tells Sarnakyle that great evils are coming. Sarnakyle is shaken, as it is impossible to tell what was a truth and what was a lie, and he leaves the Mage clans once again to seek the truth. He never returns, and his name becomes legend.

Flash forward about seven hundred years. Two of the Prime Evils have been captured in soulstones, and the final Prime Evil, Diablo, is about to be confronted by the Horadrim army led by Jered Cain. A massive battle ensues, where Diablo barely escapes with his rearguard. After seeing to their losses, the Horadrim begin to pursue.

Up in the lands, Siggard is living in peace amongst the Northmen. A sage comes to him and leads to him to a barrow, where the remains of Sarnakyle have lain buried for over six centuries. Siggard goes to the barrow, where a projection of Sarnakyle informs him of what the wizard was able to learn in his final wanderings, including a great secret that the Angels will kill to protect. He leaves to contemplate this, but Tyrael appears before him and says that his services are once again needed to capture Diablo. Reluctantly, Siggard heads south.

In Westmarch, Jared Cain and his forces are pursuing Diablo and the remnants of his army. After the trail grows cold, the Horadrim are given shelter at the Monastery of the Sightless Eye, the home of a female order of healers and mystics. There, the Abbess informs Cain that there are rumblings of something evil to the north, and he takes a small group of Horadrim to investigate.

It turns out that what he has found is the rearguard of what is left of Diablo's army. The Horadrim are ambushed, but at the last minute they are saved by Siggard, wielding Guthbreoht like a demon. Siggard explains who he is, and that he has seen the main force nearby. Cain gathers the rest of his army, and they find Diablo and fight a pitched battle. Once again Diablo escapes, but not before fighting Siggard. During the melee, Siggard discovers that Diablo's sword has been enchanted with a glyph of unbinding, as the demonic blade shatters Guthbreoht. Siggard leaves the Horadrim, inconsolable.

After Cain and his army have left in pursuit of Diablo, Tyrael appears to Siggard. Siggard holds up the shards of Guthbreoht and says that he is finished. Tyrael reveals that the only other person he has ever known who had Siggard's type of immortality was Velund the Smith, and sends Siggard off to find him. Siggard finds Velund on an island, where the smith agrees to remake Guthbreoht with even stronger enchantments. Guthbreoht is reforged and renamed, and Siggard goes off with his new sword to find the Horadrim.

As Guthbreoht is being reforged, Cain and the Horadrim come across the burnt out ruins of the Monastery of the Sightless Eye, which has been razed by Diablo. The Abbess, along with the handful of survivors, pledge themselves to become a military order, and join the Horadrim in their fight against the demonic forces. This time, the trail is fresh, and allows the Horadrim to pass Diablo's army and fortify themselves ahead in the town of Tristram.

Siggard, guided by Tyrael, arrives at Tristram and rejoins the army. While they are waiting for Diablo to appear, he begins to fall for a local woman, who has lost her husband in a recent epidemic. And then, as the friendship begins to turn to a romance, Diablo appears.

To the horror of the defenders, Diablo has managed to reinforce his army. A brutal siege begins, where the Lord of Terror vows to destroy all of the Horadrim for the capture of his brothers. As the situation becomes desperate, Siggard and Cain lead a foray out during the night, where they capture Diablo in the soulstone. Without the power of Diablo to keep them in the mortal realm, the remainder of the demonic army vanishes.

As the leaders of the Horadrim celebrate the defeat of the last Prime Evil in the house of the mayor of Tristram, Tyrael appears, and Siggard states that the cost of the angels' secret has been too high. Despite Tyrael's warnings, Siggard reveals the truth: the angels and demons are of the same blood. In the distant past, some angels settled in Heaven while others settled in the Burnings Hells, fascinated by the chaos of the place. Those who settled in the Heavens became ethereal, creatures of the noblest aspects of their nature, while those who settled in Hell were overcome by the basest aspects of their nature, and were warped in both spirit and physical appearance by the place.

As soon as the secret is out, Tyrael uncloaks himself and uses his power to subdue the entire room. As the Archangel's sword is raised to kill all who have heard the secret, Siggard manages to convince him that the Horadrim are necessary, and without them the Prime Evils will escape their prisons and reign unopposed. The Horadrim promise that the secret will remain within their order, and Siggard, feeling a bit unwell but not understanding why, goes to visit his new love.

On the way, Tyrael appears and tells him that his life is ebbing. Siggard has finally found love, which is the only thing that can bring peace to his tormented soul, and death can finally claim him. Siggard protests that he now has a reason to stay, but Tyrael points out that Siggard's family has waited for him in the afterlife for seven centuries, and it is now time to join them. Siggard sees his wife and daughter again, and reaches out to them, breathing his last breath as he does.

Cain comes out to discover Siggard is dead, and Tyrael explains what has happened, instructing that the warrior should be buried like a hero, his sword with him, until the blade chooses a new master. Siggard is laid to rest in the old Tristram church, while the foundation stones for a new cathedral to house the soulstone containing Diablo are placed by the Horadrim and Sisters of the Sightless Eye.