Necromancy

"The sun-children called us monsters and heretics for centuries. Let's not disappoint them, shall we?"

Do not ask an Esclarmondean about necromancy. The peaceable (or merely passive-aggressive) deliver a painstakingly detailed and suspiciously patronizing lecture on ancestor-worship, food preservation and how they are not the black-hearted mages the Gheisigians say they are. The forthright or spiteful may respond with anything from demanding an apology to outright physical assault. Almost no one will say the Gheisigians see old enemies everywhere and invite you to observe some improvements to the traditional rites they have been working on.
If they do, excuse yourself and do not ask again. They may have gotten further next time.

Utility

Necromancy has traditionally been used for three reasons in Esclarmonde: to mummify their dead, preserve food, and consult the ancestors. The first is accomplished by carving runes of inversion and memory (a square arch and a mirrored N) into the subject's torso and forehead which are dusted with blackroot powder, harnessing deathly energies within the corpse to kill the concept of decay afflicting them.
Its use to preserve food, which removes the rune of memory and requires the meat to be heated over a blackwood fire, supplements to Esclarmonde's main methods of drying and smoking. This innovation was further driven by their flight up into the mountaintops, and Esclarmondeans take a good amount of pride in this knowledge, hard-won from the elements and created out of necessity by the hardship and suffering their ancestors went through.
The villagers also know how to get into the correct meditative trance to approach their ancestors in the village and ask for guidance, using stone knives located at each pedestal to erode the boundary between them and the dead to communicate better. The Council has more knowledge of the full procedure, which requires blackroot smoke and a particular drumming rhythm. This allows clearer communication with the illustrious dead in their hut. It is a very slow process, because the dead move slowly. Of late, however, it seems that even the ancestors recognize the urgency of the situation, their movements far more fluid and natural than they have been in years.
Before the Esclarmondeans settled in the mountains, animal blood was used in place of blackroot. This merely added necromancy to the allegations of cannibalism from the Gheisigians, who saw corpses being smoked over fires like so much meat and drew their own conclusions. After fleeing to their current location, they quickly replaced blood with the magical and far more potent blackroot which grows best in the mountains. The plant stores magic throughout its entire structure, imparting a peculiar longevity onto nearly everything it comes into contact with.
The Black Rites are both gross misuses of these procedures and their only innovation, far closer to "true" necromancy as it is practiced elsewhere than the primitive form that exists in the Gray Village. It requires more complicated ingredients and procedures, but rejuvenates corpses and provides clearer communication with the dead, with the potential for reanimation and control. However, it can no longer be used for food preservation.

Manufacturing

The manufacturing involved is fairly simple. Blackroot crops must be tended to; stone knives must be made, chipped out of stray rock. Blackroot is farmed by the whole village as one of their staple foods and the stone knives are often made by men who are good at crafting. There is no strict gender or class divide, however.

Access & Availability

Every resident of the Gray Village is familiar with proto-necromancy, though not everyone is involved in carrying out the rituals. If there are any harmful side-effects from the long-term consumption of food preserved with undeathly energies, Esclarmonde has managed to avoid them.
The Black Rites, as well as those use them, are only known to its practitioners.

Complexity

Both forms of necromancy are fairly simple to learn as long as one has prior knowledge of smoking meats, which is used to prepare the body. Beyond that, both processes use stone knives for rune-carving and blackroot powder to infuse magic into them. The Black Rites require a more involved process: candles are burnt, magic circles are drawn, blood is spilled and the sun is cursed to summon the dark energies other necromancers seem to use.
The average resident would be able to learn the new necromancy procedures fairly quickly. Even the intricate magic circles would pose little obstacle to the oldest residents. Whether they will accept those practices or denounce them as sacrilege and desecration of the ancestors' bodies is another question.

Discovery

The proto-necromancy which sees everyday use in Esclarmonde was invented by the generation that would eventually flee to the mountains. To better preserve and commune with their ancestors, they modified old rites in pursuit of their goals.
The necromancy which the Gray Village has flirted with in its past and present (nicknamed the Black Rites) is heavily influenced by Gheisigian ideas, and worshipers of Solnos in particular. In the early days of the Empire, necromancers from various conquered regions successfully waged guerrilla wars until universal cremation was implemented and Solnos's priests executed them all with sunlight strikes, burning many innocents to death in the process. Necromancy is reviled in Gheisigis to this day and anyone who practices it is said to be dishonorable and cold-hearted, willing to put innocents in danger to reach their goals. The experimenters of the Gray Village prefer to look at the Empire's stories as indicators of what they themselves may someday achieve.