Necromantic Mummification

Whilst many cultures have funereal customs which involve the embalming of the dead, there are certain practices which have been used over the millennia to specifically prepare corpses for necromantic reanimation. Generally termed "necromantic mummification", there are several different practices which lead to similar results.

Mummification in Tzim Tevash and the Dvergar Holds

The earliest dwarven practitioners of necromantic mummification are believed to have been the inhabitants of Vash Ossai, though the particulars of their methods have been lost to history; the practice was however widespread in Tzim Tevash, from the time of the Faceless Kings and the reforms of Alavar Scriptorum, where it was strongly associated with the cult of Khetha. The practices of the Kheth-priests involved removing the internal organs of the corpse, the cavities of which were then packed with bitumen and various salts in order to remove all moisture, and the corpse then placed in a vessel full of similar salts for several months. Once thoroughly desiccated, the corpse would then be removed, anointed with sacred oils, and wrapped in linen bandages inscribed with ritual invocations of their deity's power. The Kheth cult would typically use these mummies to guard the sacred catacomb-tunnels in which the dead were entombed; there are also rumours of rituals which allowed the mummies to become repositories of knowledge, through the precise details of these methods were always a closely guarded secret of the Kheth cult.
Following the reforms of Alavar Scriptorum, the practice of necromantic mummification was outlawed; it is believed to still be carried out by the Dvergar, and perhaps also in secret by the followers of the Gods Below within other Tevashi communities.

Mummification in Terianis and the Raths

The High Elves of Terianis - who have no legal nor cultural prohibitions against the use of necromancy - use a different process of preserving the dead for reanimation, but which produces results which are ultimately similar to that of the Tevashi. In this process, it is said that the blood is removed from the corpse and replaced with a mixture of pine sap, honey, and the resinous excretions of certain insects, after which the corpse is placed within hollow log that is then packed full of woodash. Once removed from the log, the corpse is painted with necromantic glyphs and wrapped in linen bandages, with an ornate metallic mask being affixed to its head prior to the final rites of reanimation being performed. These masked mummies are used as guards and assistants by powerful Teriani necromancers, and occasionally as shock troops by the military forces of Terianis.
It is sometimes said that a handful of raths have managed to steal the secret techniques of the Teriani and are capable of producing their own mummifed servants; whilst most raths do not strictly reject the practice of necromancy, it is generally considered a dangerous branch of magic that is capable of causing immense harm if misused, and in any case this practice appears to be rare within the raths.

Mummification in the Khanates

Whilst among the orcs of the tribal alliances that once formed the Urkhaganate the dead are traditionally burned upon pyres and their ashes scattered across the plains, there is a parallel tradition of mummification that existed even before the rise of the first Tulkhan. During the time of the Urkhaganate, it was common for the bodies of revered spiritual teachers to be preserved following their deaths, in order that their wisdom not be lost; the most common method was the removal of the skull, which might then be enshrined at some sacred site, but in some situations the entire body might be preserved. This was typically performed in particular areas of the high mountains, where the bodies would be immersed in near-frozen pools of saltwater and left for several weeks, before being removed, cleaned, dressed in sacred regalia, and enshrined in caves where the rites of reanimation would be performed. The creation of these "eternal saints" was not considered necromancy - which was otherwise strictly taboo - provided that the one to be mummified had consented to the process prior to their death; some have claimed that mummies created through this process retained their intellect and personality to a greater extent than those created by the Tevashi and Teriani.
It was considered taboo to apply this process to the body of the Tulkhan themselves, out of a concern that it might interfere with their unbroken cycle of reincarnation; indeed, at least one account attributes the collapse of the Urkhaganate following the death of the 8th Tulkhan  in 62AK to the supposed theft and reanimation of the Tulkhan's body.
Following the fall of the Urkhaganate, this practice of mummification has generally become rarer. In modern times, it is practiced only by a handful of traditionalist sects among the Dovkoshi, and not at all by the Zargadalin, whose Tulkhans have since declared the practice to be forbidden. The Ikyeruns, conversely, are believed to use the practice widely, though as with many aspects of Ikyerun spirituality, there is a strict code of silence applied the matter.

Mummification in Volsanger

Prior to the Black Wind  disaster of 545AK, it is said that there existed a tradition of bog-mummification in parts of Volsanger, despite the wider cultural taboos against necromancy. Such things were said to be the work of a kind of magician known as myrgalan, who dwelled outside the structures of the Volsangan clans and who took responsibility for protection against supernatural threats. Little is known of the specifics of the practice, which was a secretive one in any case; when the Black Wind hit Volsanger and the undead began to rise across the land, many came to blame the myrgalan for the disaster and a great number of them were killed or left to fend for themselves when the clans withdrew to the fortress of Ulfgart.

Mummification in Maddur

According to some sources there exists a long tradition of necromantic mummification in the Kingdoms of Maddur, albeit one which has generally been practiced in secret. It is said that certain covens of witches drown their enemies in the peat bogs, leaving them there for decades before reanimating them as nightmarish undead servants which share many of the characteristics of the mummies that are known of in other parts of the world. Some scholars have suggested that there may be a link between the practices of these Madduri witches and the myrgalan of old Volsanger, though the truth of the matter is unclear.