The kingdom of Khandaras has fallen into chaos. An unknown force of evil has swept across the land, plunging it into civil war and terrorizing the populace. A mad king, his missing son, and a mysterious Archbishop are all pieces to the puzzle that faces you. You have journeyed to the source of the evil, the town of Tristram, now inhabited by only a handful of survivors. The cathedral there is built over the ruins of an ancient monastary, and now eerie lights and sounds are heard echoing through its abandoned halls. Perhaps the answer lies within the remains of a forgotten past.
Not long ago, before the betrayal of Arch-Bishop Lazarus and the freeing of Diablo, a Dark Mage was seen on the outskirts of Tristram. Many claimed that he often lurked near the cemetery at night. As this skulking figure did not appear to harm the graves, the townspeople left him alone. One evening smoke came drifting from the soil, as from a smouldering fire. An orange glow from below lit up the tombstones, and someone saw the Dark Mage descend into earth itself. The smoke dissipated, the glow faded, and the cemetary was still. Whispers of evil sorcery and necromancy filled the tavern's gossip for a while, but were soon forgotten as King Leoric grew madder and other troubles plagued the town.
Shortly before the Hero came and descended into the depths below the Monastery, the ground began smouldering again in the cemetery. A passing traveller told of spying a cloaked figure fleeing from the smokey site. Splattered with a thick, glowing substance, the Dark Mage ran to the river and crossed the bridge, where he collapsed. To the traveller's unbelieving eyes, the stained, glowing body of the mage seemed to dissolve and melt into the hearth, the soil greedily soaking up the remains.
Alarmed, some of the townspeople investigated the area by the river. To their dismay, they found an unclean, alien growth near the spot where the Dark Mage fell. A hard, dome-like shell, inpenetrable and bizarre, sat in the centre of the large atrocity. Since a small a small meteorite had fallen and exploded at this same location years earlier, it was now a place not only to be avoided, but also to be feared. The people pitied the poor Farmer whose land was affected, and many were concerned for his sanity, as he had taken to talking to his cattle for hours.
Disturbed and filled with dread, the people of Tristram have lately had many tragedies befall them. Signs of evil and chaos are everywhere, and the odd events by the river and in the graveyard are only a few of the many horrors that they have to contemplate. It is their hope that the Hero can unravel these mysteries as well as defeat the Lord of Terror, Diablo.