Greater demons are the largest members of the standard demon family, the other two being the Imp and Lesser demon. Greater demons are "greater" based purely on the fact that they are, indeed, larger. These monsters are most often found in places that are already hazardous, such as the Wilderness, or remote locations such as the Brimhaven dungeon.
These monsters are occasionally used for training, but as they drop very little of value they are largely avoided. They are an irritating slayer task because of their difficult locations and lack of interesting drops. Beyond a rare rune full helm and accursed ashes these monsters produce little else of interest beside exp and a great number of injuries to the player.