Rising from the floor of the heart chamber is a well of arcane power. Filling the well to within a couple inches of the top is an inky black liquid that drinks in the light. Within this liquid, shadowy landscapes rise and fall sprinkled with dozens of tiny red blips. Evenly spaced around the side of the well are three niches, each containing a bone fragment within an ornate reliquary.
The Demonscope serves three crucial functions. First, it serves as a potent scrying device focused solely on demons. It automatically senses the location of any demon in a 5-mile radius, bypassing any spell resistance they possess. Second, it focuses divine energy to power the wardstones, a series of smaller artifacts that together create a physical barrier against demons (see below). Finally, the Demonscope creates a massive dimensional lock effect that extends in a 250-mile radius around where it is held. Although this effect does not prevent demons from entering, it does prevent them from teleporting out into the surrounding lands, and it prevents anyone from teleporting in.
The Demonscope requires constant attention and maintenance in order to function. Powered by a combination of intrinsic magical power and the magical potency of the demon that is imprisoned within it, the artifact requires that a careful balance of power be maintained at all times, and the demon kept in check. It takes the combined efforts of three strong-willed paladins to maintain control over the demon. If one of them fails, the demon eventually overpowers the other two and begin to corrupt the artifact itself, although this takes several days. The easiest way to destroy the artifact, however, is to remove the bone shards. Without the shards, the paladins are unable to control the demon, and it only takes a few hours for it to break free from its prison.
GameMastery Module D3: The Demon Within. Copyright 2008, Paizo Publishing, LLC. Authors: Stephen S. Greer and Tim Hitchcock.