On the Preparation of the Corpse, Volume One: The Acquisition of the Corpse
While the Arts of Necromancy are only illegal in the province of Morrowind, few citizens of the Empire have an enlightened view of our Art. Thus, the acquisition of corpses on which to experiment is often difficult.
In Cyrodiil, a few Necromancers who have served the Empire are given the corpses of criminals and traitors to use legally. This provides those who have acquired such a post with a fresh supply of corpses, most of them young, strong, and intact.
In Morrowind, the outlawing of Necromancy would make its practice impossible were it not for the fortunate institution of slavery. While the Temple will investigate obvious signs of Necromancy such as hastily emptied graves or ash stolen from one of their ashpits, a careful and discrete Necromancer can thrive in Morrowind by taking slaves at a modest rate. Most will assume the slave escaped or died in the Ashlands.
Finding suitable corpses in Black Marsh is nearly impossible due to their rapid decay. There are also diseases, Argonian tribesmen, and other difficulties that must be dealt with. I know of only a few Sload Necromancers who operate successfully in Black Marsh, and even they stay near coast.
While the forests of Elsweyr pose some of the same problems as those of Black Marsh, the deserts preserve corpses for hundreds of years in a way that requires very little preparation. Khajiit of the desert tribes are often buried with only a small cairn of stones which are easy to find and uncover. The Khajiit show remarkably enlightened indifference to graves being uncovered. It is said that in the port of Senchal, one may purchase anything one desires. This is true if you desire fresh corpses.
While few Bosmer perform Arkay's rituals when burying the dead, the more primitive Bosmer still practice cannibalism upon their enemies, which reduces the number of available corpses. As would be expected from such a backwards people, they have an intolerance of Necromancy that goes beyond all reason. Many Necromancers who practice our Arts in Valenwood become "one with the trees" themselves.
Summerset Isle is even worse in some ways. Some Altmer born into the most respected noble and scholarly families are actually allowed to study the dead in the open. Their research, however, seems to be centered on finding ways to extend their lives even further rather than the more practical uses of our Art. A Necromancer of any other race caught in Summerset Isle can expect the worst possible punishments.
In Hammerfell, where worship of Arkay is strongest, the dead are almost always subject to Arkay's Law. There are exceptions after large battles or in remote areas where death occurs far from meddlesome priests. Fortunately, the dangerous terrain and creatures in the deserts and mountains of Hammerfell makes the acquisition of corpses possible, though they are often in poor condition and require special care in preparation.
The newly formed Orsinium presents a unique opportunity. As you know, Orc corpses are among the most sought after for the durability of their skin and the strength of their bones. If King Gortwog will listen to reason, we could offer the services of our Art in defense of his young nation in exchange for disposing of the Orcish dead. A mutually beneficial arrangement as I'm sure the Orcs will agree. To this end, a delegation has been sent to Orsinium, though we have not yet heard any word on the state of these negotiations.
In my native High Rock, traditions dating back to the witch kings and nomadic horsemen mandate cremation of the dead. This is practiced almost without exception in the north, through an Imperial burial in a tomb or city cemetery is more common in the south. There are still many corpses easily taken from the battlefields of the War of Betony and the lawless times that followed. There are even rumors that King Gothryd of Daggerfall may institute the Imperial practice of donating the corpses of criminals for Necromantic study as a deterrent to the bandits and pirates that still threaten the Iliac Bay.
In Skyrim, the cold weather and isolated terrain allow a few Necromancers to operate freely. Alas, the availability of corpses is limited to Nords who die from exposure or in battle. While the cold is preservative, the snow makes these corpses difficult to find. More research dedicated to the magical detection of corpses would be invaluable to the Necromancers of Skyrim.
The Sload are the most famous Necromancers, but little is known of their native Thras. In Tamriel, Sload only practice Necromancy on other races. It is uncertain whether this is true in Thras as well. If so, it would explain the number of slaves that are purchased in Tear by Sload merchants and the rumors of Sload airships carrying corpses from Senchal.
These difficulties lead many Necromancers to create their own corpses. While I prefer to work with those who have died a natural death, a more expedient approach is sometimes necessary to further the study of the Art.
While the Arts of Necromancy can be practiced on animals, such experiments rarely produce interesting results. The servant's ability to follow directions seems to be related to the subject's intelligence in life. While raising the corpse of a man, elf, or beastman can produce a useful servant, the corpses of animals produce mere guard dogs at best. Often a raised animal is unable to distinguish its master from the rest of the living and many amateur practitioners have been torn apart by the animal servants they created. Let such stories be a lesson to you.
On the Preparation of the Corpse, Volume Two: The Skeletal Corpse
When raising a skeleton servant, it is most important that the body of the skeleton be complete. If the skeleton is missing crucial bones, the results can be frustrating. One should only attempt to raise skeletons when you are sure that all or nearly all the bones are present.
While the magic involved in raising a skeleton will assemble the bones in the proper order, skeletons may be strengthened considerably by the addition of support on their joints. The most common are leather straps that bind the bones together more tightly. Some practitioners also drive metal spikes are between the joints, which is more expensive and time consuming, but they protect the servant where it is weakest. The details of this are unimportant as even an amateur can strengthen a skeleton significantly. Only practice will reveal the best methods of binding and reinforcing the skeletal servant. Amateurs often make the mistake of binding the bones too tightly, limiting the skeleton's movements and making it useless. Again, only practice can give the necessary experience in these matters, though it is best to err towards tight bindings. One may always loosen them at a later date.
One more note to the student: While most undead can be raised again and again, skeletons are often damaged in ways that make raising them again impossible. This is another reason that care should be given to the skeleton's preparation. Too many young Necromancers raise every skeleton they see with little or no preparation at all. Given the difficulty of obtaining corpses, this kind of inefficiency cannot be tolerated.
On the Preparation of the Corpse, Volume Three: The Fresh Corpse
Fresh and decayed corpses are those that still have flesh upon them. If their decay is advanced, or if you wish a skeletal servant instead, place the corpse along a coast or in a swamp or marsh. Animals are the Necromancer's greatest allies when it comes to stripping the flesh from a corpse. The ravenous mudcrabs of Morrowind can strip a corpse down to its bones in a matter of days. Lesser crabs in other provinces can do the same in a matter of weeks.
If you wish to create a zombie servant, one need only bring the corpse to a suitable site and enact the proper rituals. However, there are a few tips that a young Necromancer might want to know. For instance, a decayed servant may be raised many times, even if they have been dismembered by those who do not appreciate our Art. If one of your servants comes to an unfortunate end, you may raise the servant again by carefully gathering as many parts as you can find, binding the bones with leather straps, and sewing the flesh (if it not too decayed) with catgut. Your servant may be weaker each time this is done, but with care and maintenance, one may raise zombies dozens of times.
However, creating a mere zombie is a method best left to lazy or desperate practitioners. With only a bit more time and effort, one may create a far more useful mummified servant.
The first step to creating a mummified servant is to soak the decaying corpse in a bath of salt or natron for at least one month. This will halt the decay of the corpse, and if the corpse is fresh enough to have an unpleasant odor, the salts will remove that as well. In a moist climate, such as Argonian or Thras, you may have to apply more salts if they become saturated. Some Necromancers remove the vital organs before or after this process, but I have never found any practical reason for doing this.
The next step is to wrap the servant in cloth or linen. This will further preserve the body against decay and, if done properly, will offer some protection as well. Do not worry if the corpse seems too stiff or desiccated to be a useful servant, the proper rituals will imbue the mummified corpse with the strength to move itself. Most importantly, you will have a much stronger servant who will follow your commands with more independence and understanding.