On the 4th of Sarapin, 426 AF, a party of leaders and nobles from all corners of Sapience gathered at the newly constructed Planetarium of the Crown at the end of Gaear Street in Hashan. The unsuspecting guests were greeted by a well-dressed man named Tavarius, who invited them to enjoy refreshments and explore the planetarium, before demonstrating a new use for the mysterious Disc of the Nocturne, one of Hashan's most important artefacts. Tavarius vanished at dawn.
Noon on the same day brought an unexpected phenomenon to the sky: the planets Noxtra, Lunastra, and Somnustra converged to eclipse the sun. As they aligned, however, the planets failed to continue on their paths, remaining at a standstill in front of the sun, and shrouding the land in darkness. Tavarius was soon found within the Vashnar mountains in the company of the Ouranian priestess Isillinde, Alariel of Hashan, the wizard Hycanthus, and Ikant of Ashtan.
A number of strange events surrounded the coming of eternal night: some were closely tied to the machinations of Tavarius, others were simply a result of the absence of sunlight, and still others signified the effect of the great shift in energies brought on by the eclipse. The tritons stationed in the undersea city of Riparium left the city in a mass exodus; the oft-heard Oracle of the Manasseh, Apollonia, disappeared without a trace; each midnight, a massive nychtaur rampaged through the city streets of Sapience; the protective spirits of the forests disappeared; a strange portal known as the Thousandth Door began to appear in various places throughout the land; ethereal nightmares roamed the land. Also coinciding with the other phenomena were the returns of the gods Thoth and Valnurana to mortal perception.
Held immobile within a mysterious ward of power, Tavarius was somehow gathering the energy from the sun, but his purpose still remained unknown. Then, in an effort to penetrate the ward, ritualists led by the Mitran priestess Aerilius unexpectedly uncovered the truth: Tavarius was none other than the feared Slith, Prince of the Undead Legions and humanity's foe since its beginnings.