The Rise and Fall of the Dark King

In the middle of the 10th century AC, the kingdom of Dreyvier was taken over by a powerful and sinister wizard known only as the Dark King. (His actual name has been removed from every history book.) This despot rose to power within the wizard's guild of Dreyvier and then took control of the kingdom after the massacre of the royal family and their supporters. Two of the children escaped and fled north.
He trafficked with dark powers, binding demons and fiends to his service along with powerful undead. After subduing the hostile forces to the south, he turned his gaze north. During the last days of the millenium, his armies threatened to overwhelm the Kingdom of Oruss, but the royal family along with the surviving members of the Dreyvier nobility, raised armies to drive back the dark hordes.
A group of powerful heroes infiltrated the heart of Dreyvier and struck down the Dark King. His death sent his followers into disarray and allowed the defenders to rally and push back against their attackers. After the fighting was done, the two kingdoms were united under the heirs of Oruss and Dreyvier and the Kingdom of Geyrvohn was formed.