According to the Wizardry Archives manual, the siblings searched for and found the armor of the fabled "Knight of Diamonds". Together, they managed to defeat Davalpus. Alavik wore the diamond armor and the weapons, thus becoming the successor to the original Knight of Diamonds. But the battle left the royal palace in ruins and the City of Llylgamyn cursed. Davalpus and Alavik vanished together with the Staff of Gnilda, an artefact that protected the city.
The Ultimate Wizardry Archives (Manual), p. 60.