The Eye was the patron figure of a cult based in Duldrus and known for having gained control over the gapers in the area. Raising in power very fast and responsible for the deaths of many brave warriors in what would become known as the War of the Eye, it was eventually defeated by an army gathered in Mirith.
Most of the information we have on the Eye comes from Alastor , during his interrogation in Mirith castle. Viewed as a god by his followers, the Eye was originally a wizard who was gradually corrupted by the use of Black Magic (Alastor could only remember that his name started with a K). At the latest stages of his transformation, the black magician lost his previous body, becoming an omnipresent and omniscient "cloud of sentient Black Magic". His cult began by then.
After being defeated at some uncertain event, the Eye wandered powerless for many years, until he chanced upon the Ice Dungeon. There, the presence of the Curio reawakened and strengthened the Eye's old capacities. However, since the Curio was fixed in the dungeon, the Eye's reach was also limited, extending only up to Duldrus.
Once his cult was reunited (or the children and grandchildren of the original cultists), the Eye sent them after Alastor, to find the way to move the Curio from its place. With the wizard's knowledge, the cultists wrapped the object in a golden fleece, that was since carried by their Archpriest.
This report from Alastor meant that Mirith would now have a specific target in the war. By killing the Archpriest and recovering the Curio, the Eye would die as well.
Easier said than done. Since the Eye could see everything, he could also predict the attack, and tried to create a diversion in Andris. The people gathered in Mirith did not let themselves be fooled, and the battle took place on the planned day. It was one of the hardest battles in history, but the citizens of Oberin left it victorious. All but one: Zexe, who led the troops and died bravely at the hands of an Eye priestess.