Daggerfall:Daedra Summoning

thumb|right|A Daedra Summoner of the Cabal of the Mages Guild
 
Although the act of summoning a Daedra Prince is no common service, it is one nonetheless. The only reason to summon a Daedra Prince is to gain possession of a certain artifact. Few can perform this service, therefore access is restricted. People of noble origin have the means to access a Daedra Summoner; it is rumored that every ruler has his own Daedra Summoner at court. Common people can access a Daedra Summoner only within the services of certain Factions. However this special service is restricted to high-ranking members within these factions and the cost are in most cases exorbitant. There are rumors, that certain Witch Covens can also summon a Daedra Prince for whoever has the required amount of gold.

Daedra Princes request a certain service from mortals that dare to appeal to them. If the mortal completes this duty to the satisfaction of the Daedra Prince, he or she might grant the petitioner possession of a legendary artifact.

Detailed Information
Summoners
There are three ways to summon a Daedra Prince:

Using the Daedra summoning service of the Mages Guild, available to members at rank 6
Using the Daedra summoning service at one of the eight Temples, available to members mostly at rank 7, except the School of Julianos (rank 6) and the Resolution of Z'en (rank 8). Note that temples will not summon Daedra who are their enemies.
Speaking to the beldam of a Witch Coven, to one of the warlock sometimes found in cities, or to the lone witch who can be found in a dungeon during the Knightly Order quest The Artifact

Daedra can only be summoned at the Mages Guild or Temples on certain days (see Summoning Days). At witch covens, however, the situation is completely different. It seems that random chance alone determines which Daedra Prince will be summoned on that particular day. You can, of course, simply visit the coven every day until they offer to summon the Daedra Prince you wish to speak to.

The only exception is Hircine, who can be summoned every day by the Glenmoril Witches. He cannot be summoned by other Daedra Summoners, even on his Summoning Day.

Sheogorath
thumb|right|The Daedra Prince Sheogorath
Although Sheogorath has his own Summoning Day, there is a 5% chance (or 15% if thunderstorm) on every other Summoning Day that he shows up instead of the Daedra Prince who would normally appear.

 

Summoning Twice
thumb|left|Hermaeus Mora, summoned a second time
Trying to summon a Daedra Prince after you've already done so once will bring up a dialogue where the respective Daedra Prince refuses to interact with you.

 

Summoning Costs
The costs for summoning a Daedra Prince are quite high, and are determined solely by your reputation with the summoner's faction. The base price for summoning a Daedra Prince is 200,000 gold. The exact costs are calculated as follows:

 200,000 gold &minus; (  &times; 1000 gold) 

This means a having a reputation of 100 with the summoner's faction will lower the cost of a summoning session to 50% of the base price.

Regarding this formula, the best choice for a summoner (if available to you) would be the Daedra Summoner of the Mages Guild, because:
Your reputation with him is the same as with The Mages Guild as a whole. Therefore, you need at least 20 successful quests for the Mages Guild for a total reputation of 100.
Summoners of Temples are only subgroups of their temples, so you only get 2 reputation points with them for every successfully completed quest. Therefore, you will need at least 50 successful quests to acquire a total reputation of 100 with them.
If you successfully complete at least twenty quests for a witch coven, you will also have a total reputation of 100 with the beldam at the end, but finding a witch coven without any hints is a difficult (if not impossible) matter. 
There is only one quest in the original game which points to a coven, Business with Vampires, which reveals the Kykos Coven in Dak'fron.
In addition, lycanthropes may get a hint pointing to the Glenmoril Coven in the Ilessan Hills, but these witches only summon Hircine.
Two other quests, The Daedric Book and The Thieves Gang), that should reveal the Skeffington Coven in Phrygias and the Coven of the Tide in Myrkwasa respectively, are broken in the original game. The covens will not be revealed unless a patch for these quests is installed.
There are no rumors or books about any coven locations. If you are very, very lucky, you may receive a dungeon map which reveals the location of a coven. However, you must be in a region which has a coven. Even then, the chances to get such a dungeon map are marginal since, according to the law of probability, the calculation   is terribly low.  

Chances for a Successful Summoning
 

The bonus is 30% and applies unconditionally for most Daedra. The following Daedra receive this bonus only during a specific weather:



According to The Daggerfall Chronicles, the maximum chance for a successful summoning is 95%. The remaining 5% is for Sheogorath's chance of appearing, which rises to 15% during thunderstorms.

If a summoning is successful but you declines the Daedra Prince's quest, waves of one of the five daedric foes will begin appearing to punish you for three in-game hours. After this period, they will return to Oblivion.

When a summoning at a witch coven is unsuccessful, the daedric foes will also appear. At guilds, they will not. If a quest for a Daedra Prince is successfully completed, you will gain +5 reputation with the witch coven who summoned the Prince and +2 reputation with its allied factions, if any exist. Considering all these factors and circumstances, it is wise to always save the game before attempting a Daedra Summoning.

Note: Gameplay experiences indicate that the daedric punishment feature only has a marginal chance of actually occurring.

Summoning Days
The summoning days are hinted at in the book Invocation of Azura.



Bugs
Nocturnal's Summoning Day is intended to be on the 3rd of Hearthfire (instead of the 8th). This is hinted at in the book Invocation of Azura, which is made less vague in the version found in future The Elder Scrolls games.
The Daggerfall Chronicles further supports the claim of her summoning day being on the 3rd.