Barriers are highly delicate and complex magical structures, requiring a long and intricate ritual to be established. The spell that is cast essentially serves to create an impassable barrier to all living entities, and can be created so that it forbids passage in both ways or just one way.
The Barrier of the Valley of MinesEditThe Barrier around the Valley of Mines was created by twelve magicians. Many believe it was created so that prisoners from the Valley of Mines could not escape. But it was actually created to "protect the ore from the menace of beliar" as mentioned in "The Almanac."
To properly control such great amount of magical power five Focus stones were needed. On the map of the Colony the magicians carefully defined the position of these magical artifacts. The pentagram was drawn over the map and the most appropriate places for the position of the Focus stones were on the points of this pentagram. There round pedestals were built and focus stones were put on them. The magicians used staffs to join their powers, but something disrupted the delicate nature of the creation spell of this barrier, and it grew much larger than it was supposed to be, trapping all twelve magicians inside.
The Barrier covered the Valley of Mines for almost 10 years. At that point Xardas and the hero found out what had disrupted the creation of the barrier. It was the power of the Sleeper that held the barrier in such dimension and when he was banned from the earth (by the hero) the Barrier fell.Rhobar. Power necessary to create it was given by King Rhobar II's Scepter of Varant and was controlled by the mages.
It was erected only to disable entrance to the approaching large Orc army. But in order to close the way in, they also had to close the way out. But the barrier was created a bit too late, because orc army already captured the outer ring of the city when it was created, so king's last troops were trapped inside the barrier outnumbered by the orcs.