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 driving from the soil, as from a smoldering fire. An orange glow from below lit up the tombstones, and someone saw the Dark Mage descent into the earth itself. The smoke dissipated, the glow faded, and the cemetery was still. Whispers of evil sorcery and necromancy filled the tavern's gossip for a while, but were soon forgotten as King Leoric grew maddened and other troubles plagued the town.
Shortly before the Hero came and descended into the depths below the Monastery, the ground began smoldering again in the cemetery. A passing traveler told of spying a cloaked figure fleeing from the smoky site. Splattered with a thick, glowing substance, the Dark mage ran to the river and crossed the bridge, where he collapsed. The the traveler's unbelieving eyes, the stained, glowing body of the mage seemed to dissolve and melt into the earth, the soil greedily soaking up the remains.
Alarmed, 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, impenetrable and bizarre, sat in the center of the long atrocity. Since 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.