The Veil is a magical barrier that separates the magical world from the natural one. At one time, the Veil did not exist and the world of magic and nature existed as one, ruled by the Elves. Then the Firbolgs and Celts came to Hibernia and conflicts arose between the groups. Rather than continue to fight with these new beings, the Elves decided to remove themselves from the world of Hibernia. Their decision would affect all of Hibernia.
The Elves used their great power to separate the world of magic from the world of nature, creating two worlds from one. To the Firbolgs, Celts, and other non-magical creatures, they left the natural world. The magical world, called the Otherworld by some, became the home of the Elves, their friends the Lurikeens, and other magical creatures. The Elves, with the help of the Lurikeens, raised a magical barrier between the two worlds to prevent the non-magical creatures from passing through into the Otherworld. This barrier became known as the Veil.
In the process of raising the Veil, the Elves attempted to pull certain buildings and areas into the Otherworld. The Elves found the structures made with their Elven magic were much easier to move into the Otherworld than those made with the wood, stone, and earth of Hibernia. One such structure, a castle known as Marrach Briollag, was a favored place of the Elves. Although it was built of stone and wood, Elven magic had been used throughout its building. Believing that their Elven magic would overpower the natural materials of the castle, the Elves and Lurikeens began to move Marrach Briollag into the Otherworld.
The Elves underestimated the powerful hold that the very land of Hibernia had on the castle. Even as the Elves struggled to move the castle into the Otherworld, the land was trying to draw the castle back into the natural world. The Elves succeeded in moving Marrach Briollag into the area of the Veil but could move it no further. The magic of the Veil had ensnared Marrach Briollag so neatly that neither side could budge the castle. Those that had inhabited the castle as it was being moved were trapped also, unable to return to Hibernia and barred from passing into the Otherworld. The castle was lost to the mists of the Veil, and it and all those that dwelt inside were forgotten until recently.
The loss of Marrach Briollag and its inhabitants was not the only thing to come from the raising of the Veil. The Elves did not realize when they raised the Veil how its presence would affect the lands of Hibernia. Magic from both the Veil and the Otherworld bled over into the lands of Hibernia, infusing the natural world with its own kind of magic. Over time the Celts and Firbolgs learned to channel and manipulate this nature-based magic. This newly gained magic worried the Elves a little, but they knew they were still safe from the Firbolgs and Celts, for only creatures of magic, not of nature, could pass through the Veil into the Otherworld.
While the Elves and Lurikeens were occupied with establishing their new cities beyond the Veil, another race of magical beings quietly moved into the Otherworld. They chose a remote part of the Otherworld as their home and began to build a labyrinthine city. By the time the Elves and Lurikeens discovered these demonic-looking creatures who called themselves the Shar, they were too well-established to be forced out of the Otherworld. The Elves allowed them to stay, but watched them closely, for they rightfully sensed that the Shar were evil.
For those that reside day-in and day-out in the Veil, its appearance is no more than a shimmer in the air, indicating the transition from the Otherworld into Hibernia. To Elves and Lurikeens that have been outside the Veil for extended periods of time, the Veil appears to them as a white, misty area full of shifting colors, as if they had walked into a cloud pulsing with light. In the area where the Shar pass back and forth between the worlds, the Veil has a similar appearance where it contacts the ordinary world. But as one approaches the Shar Labyrinth, the Veil becomes a swirling mass of black and gray clouds that pulse with red, orange, and golden light, for the Veil has absorbed some of the evil magic of the Shar.
To the Firbolgs, Celts and Sylvan, the Veil appears as the white, misty area of shifting colors, if they are able to even see it at all. In most cases, those not of the Veil cannot see its magic. This lack of vision of the Veil caused a problem for the Shar when they were forced to ask the people of Hibernia for help. To aid the Shar, these races must not only be able to see the Veil but to pass through it. Thus the Shar, much to the dismay of the Elves beyond the Veil, used their magical abilities to open the barrier between the worlds, allowing all of Hibernia to enter the Otherworld for the first time.