About Demonology in Valon

Demons and Demonology (and Undead):

Summoning:

To summon a Demon, a GATEWAY into the Demon World must be made, generally using a spell or ritual (of a minimum 4 IME, ISE or Ki, etc.), unlike the MONSTER SUMMONING spell which summons a monster of the appropriate size from a random place, extra fine tuning must be available to fix on the Demonic plane.
There must be some way of tempting the Demon to come through.
There must be a Name or specific enough details to focus on one particular entity or locus.
As well as the ritual / spell required to open the gate or window, a CIRCLE OF PROTECTION is generally used to protect the summoner from possession.
Power (IME, etc.) / sacrifice is necessary to bring the Demonic Spirit through, equal to the soul size (IME + ISE + Ki) of the Demon. Permanent power will enable the Demon to come through permanently, whereas temporary power sacrifice brings it (f. ex) into the CIRCLE OF PROTECTION where it can be bound to do a task for (f. ex.) 1 day, whereafter it must return to whence it came. Generally Human or animal sacrifices are used to provide the permanent power, but Humans (etc.) often have more soul power, so are more valuable as a sacrifice. Pregnant mothers of course are doubly valuable, whereas virgins have more symbolic significance.
A Temple dedicated to the worship of a particular Demon would of course make it easier to focus on the summoning of that entity.
Certain times of the year are supposed to be more significant in that it is easier to make a gate between worlds at these times.
The places and times depend on many factors, but All Hallows Eve is generally assumed to be a night when the barrier between C'thain and the Demon / Spirit World is particularly thin. Full Moon is also significant in that it is often easier to encite Humans into doing less logical things at this time. Ley Lines are magnetic power lines in the earth; where these cross often produces a comfortable or powerful feeling. There are other power lines / crosses of which Humans are less aware, that can be (in)auspicious for summoning or protect against such.
Candles made from Human fat, Parchment made of Human skin, despoiling a virgin, a victim ready to be tortured, a willing sacrifice ready to be possessed, etc.; such things symbolising the kind of things Demons like to do in C'thain act as a temptation for it to step through the gateway.
Note that Demons not bound into a body cannot affect the material world except through spells, just like a Ghost. Sensitive persons can sense them in the same way as they can see or sense Ghosts, though Demons look and feel different. Such demons make excellent spies. There are several sensitives in the Orders.

Known Names / Characteristics / Attributes / Attitudes / Interrelationships / Ranking of Specific and Types of Demon:

§ Demon of Nasty Surprises called Trepidation of the Lower Circle: Low status, but can do a few minor things like make nasty traps.
§ Demon of Embarrassing and Uncomfortable Knowledge called Poison Mirror of the Central Circle: Medium status, good at CLAIRAUDIENCE and CLAIRVOYANCE.
§ Demon of Spying called Sneak Preview of the Lower Circle: Low status, can become INVISIBLE even if embodied.

It is known that Demons can breed with Humans, though it is very rare and known only to happen in special circumstances. The Human or Demon must have physically entered the appropriate world which is very difficult and would require a full GATE to be constructed (more than 4 IME, etc.,). Such a Gate exists and was inadvertently opened to allow the entry of thousands of Demons into C'thain, causing the Great War, where they killed and maimed thousands of people in the Kingdom of Reshall. Fortunately for the world of C'thain, the Demons were unprepared and most of them were unable to survive in our world for long, making them weak and easy to defeat.
It is, however possible, that some Demons or their offspring still remain in the world of C'thain. Their characteristics are unknown, though horns, fangs, scales, tails and suchlike might be expected.
It is said the Paladin Varidor and the Priest Gorzak, amongst others, went into the Gate to close it, and succeeded. These individuals were soughtr some time ago, but it seems that Varidor was missing presumed dead; he never came back from the Gate, and the High Priest Gorzak had passed away due to old age, taking the knowledge of the Gate with him. The Robbinian Eloisie woud like more information about this.
There is a rumour that the Baroness Keruna of Igor is a Demon or a man in disguise, and she has been observed briefly at court in Senacran recently. This small, delicate woman did not appear to bear any Demonic traits so far as was observable, and she did not appear to have any problems with reacting in a socially correct way, but there are many rumours about various atrocities she has supposedly committed, though no witnesses or evidence has ever been found. She will continue to be watched by Reshallian agents.

Known Demonologists, Living and Dead (Taken) / Characteristics, etc.:

The Cult of Shamarr was discovered around 400 years ago in Valdelon. They had been summoning minor Demons for some time and had plans to bring in a major one for their own gain over others, to be worshipped as a false God and they as its Avatars.
A group of 3 Demonologists were responsible for this, their leader called Sirdalle and her associates and lovers Vaul and Gerivan.
A rival cult discovered the plot was a ploy for the Demons to gain a foothold on this world and cause its destruction but they discovered this too late; the Demon had already been summoned and it fled in the battle between the two cults. They hunted the Demon all over the continent before they finally tracked it down and exorcised it with the help of GOD from its now mad host Vaul. What later became obvious was that Vaul, under coercion from the Demon of Persuasion Sybelline of the Inner Circle had built the Gate to Hell in Reshall, but this was not discovered until it was opened. Most of the cult died in the battle to exorcise the Demon, but one survived, and he renounced his status as a budding Demonologist, and became a devout follower of GOD, giving all of his knowledge and ability to the fight against Evil.
Much of the fighting was apparently with Swords of Cold Iron, but some of the weapons had been enchanted to steal away the victim's life energies, it is not known how. Most of these weapons were destroyed, but one curved knife was never accounted for - the Knife of Sirdalle. It is uncertain if all of the Demonologists were accounted for, one or two may have not been at the ceremony that night.

Many countries on this northern continent of Norama, such as Valon and Tarantis, have strict laws regarding Necromancy, Demonology and Black Magick and such; it is forbidden. There have been several persecutions of Witches and Warlocks; it is certain that many innocents died in these, but also certain that many truly evil cults were nipped in the bud.
The Patriarchy continues to push for such practices to become forbidden in Reshall as well.

Reshall, especially Meriandor and Vrakir, is a likely place as all persecuted religions or cults have had a tendency to end up here as there were no laws there in the beginning.

There are no known living Necromancers.
About 100 years ago the famous Necrophiliac Necromancer Naston de Leton lived north of Marque on the Tarantis border. He stole away recently dead and buried young women for carnal pursuits, keeping them in an ice cellar when they were not serving their master, where he would warm them up for a couple of hours in front of a roaring fire and have them dress one another in all manner of revealing clothing before having his way with them. He was a master of disguise and more mad than evil. He was also an expert in persuasion and law, raising his victims in a hut in his garden which legally was on the other side of the border where actual Necromancy was not forbidden at the time.
Tarantis then made Necromancy illegal, proclaiming the news only in town squares, and Naston was caught adding to his harem before he became aware of the news.
He was executed after questioning which led to the capture and subsequent execution of 4 other Necromancers.
It seems that Necromancers tend to operate alone more than Demonologists. This may be due to Demonologists needing more power / worshippers for their pursuits.