A demon in GemStone IV is defined as "a being from another dimension." Though demons are not generally evil or malevolent by nature, they are chaotic and, unsurprisingly, prefer not to be relocated from their original plane of existence to do the biding of unknown persons. Summoning demons to our plane usually causes them great agitation or fear, condemning them either to servitude or warfare. Woe is the summoner who fails to maintain control of their beast, death by the demon itself, legal repercussions, or an angry mob is sure to ensue.
Lesser demons (inclusive)
Lesser demons are the lower of the two classifications of demon, being contrasted with Major demons. This class includes creatures with a wide range of attributes and power, from weak, nonsentient animal-like beings to powerful and intelligent beings. The most humble of the lesser demons are referred to as minor demons, which are often seen performing menial tasks in service of sorcerers around Elanthia as a result of Minor Summoning. However, other lesser demons are capable of casting destructive magic and/or possess significant battle prowess, most commonly finding their way to Elanthia by failed Planar Shifts. As there is no specific name for these more powerful lesser demons, lesser demon may also be used to refer exclusively to those demons with power judged to be intermediate between major demons and the minor demons. In conclusion, this semantic overlap requires some specificity in order to achieve clarity when discussing non-major demons.
Lesser demons (exclusive)
These demons are capable of participating in combat and are also categorized as extraplanar beings.
These demons are not capable of participating in combat with the exception of interaction with Balefire (713); they are primarily used for utility. Minor demons are summoned using Minor Summoning (725).
Behind the Scenes
"Lesser demon" was originally used in The Official History of Elanthia to describe the demons used at the battle of Maelshyve, much as "minor demon" was used several years earlier in The Legend of the Necropolis of Etrevion to slaughter ordinary soldiers. At the time "lesser demonic" were used to classify the power of undead between Level 16 and 25, with "undead of the greater demonic" being those higher than Level 25. While this seems incredibly low by today's standards, it would have been formidable for most adventurers when the story was written. The banshee was one of the most powerful creatures in existence, with most of her horde implicitly being comparable to monsters in The Graveyard. In the original Rolemaster level scaling, the most powerful demons were around Level 50, while the most powerful dragons were around Level 100. The avatars of deities were typically between Level 100 and 200. In this context an extremely powerful 8,000 year old Elven sorcerer might be Level 40.
Whether "demons" are inherently malevolent has fluctuated over time in GemStone. In the I.C.E. Age they were inherently evil and destructive, originating in more chaotic planes of existence of corrupted essence. However, in some cases they originated as corrupted souls of this world making a blurry distinction with the undead, and some chaotic or utterly alien beings were also called demons. In contrast, the deities of Orhan (Liabo) were extra-planar in origin, but were not demonic. This is still true in DragonRealms, but in terms of theology, the Arkati are interpreted as a race of this world.
The demonic were treated as inherently malevolent in the late 1990s, but there was virtually no presence of them in the game. Some pushback existed to redefine demons as referring to any extra-planar being whatsoever, and this very liberal sense of the word is codified in the Enchiridion Valentia. When the elementals documentation re-established that they were extraplanar but not demonic, it also asserted that demons have an "intense hatred of life." Similarly, the Ithzir are extraplanar beings, but are not demons. The very malevolent vathors, oculoths, and necleriine were made around second Griffin Sword War, with the demonic since being treated as very dark. Whether they are necessarily extraplanar is also ambiguous. Althedeus was a primordial "demon" formed by the Ur-Daemon War, the Queen of Castle Anwyn transformed into a demon by being corrupted by a Vvrael scroll, there are demonic offspring with lifeforms of this world south of the Demonwall, and other examples of hybrids or artificial constructs.