A Calumn is a Wyrm domain within the Near Umbra. They develop when a particularly strong, negative emotion is expressed in a place within the physical world that it leaves a print within the Umbra. It is a magnet for Banes and Spirits that live near a Calumn show signs of their respective emotion and even inanimate objects becomes tainted by the proximity. If somebody stays long enough within a Calumn, it is very likely that his thoughts are also affected by the emotion until the person eventually develops a derangement.
A Calumn could also be the place of a Hellhole.
Calumns are often the home of various Banes who choose such places for slumbering and restoring their powers.