Necromancy is an ancient school of magic. Since the dawn of time, magic users have been using magical techniques to control and interact with dead spirits. Some ancient cultures held a great respect for such magic users, but in Medieval Europe, the attitude was different. In both Christianity and the popular versions of paganism at the time, Necromancy in any form was looked down upon. Opinions ranged from seeing it as disrespectful to the deceased to seeing it as actively unholy, but seeing it as a negative was universal. That all changed with the death of Ivar the Boneless.
Ivar was one of the leaders of the Great Heathen Army which invaded Great Britain with the goal of conquering it instead of simply raiding the island. He was well respected by his men as a great military leader, but succumbed to an unidentified illness and died of this disease. The religious beliefs of the Norse people dictated that men who died honorably in battle spent their afterlife in Valhalla or Fólkvangr while those who died of sickness spent their afterlife in Helheim.
Valhalla and Fólkvangr were both regarded as pleasurable afterlives (by the standards of the Norse who enjoyed the excitement of combat). In modern terms, they are regarded as examples of “Heaven”, the category of pleasurable afterlives. Helheim, meanwhile, was described as cold and dark and was seen as a torturous afterlife. In modern terms, it is regarded as an example of “Hell”, the category of unpleasant afterlives. In fact, it is the source of the term “Hell” itself.
Ivar was beloved by his men, and they despaired at the idea of their leader being subjected to such suffering in the afterlife. However, he was lucky in that there were a small number of necromancers in the Great Heathen Army. They only filled minor roles in the force, but here they could have a major impact. They proceeded to kill themselves to follow their lord. There, they used their mastery over death to walk through Limbo with impunity.
The necromancers were able to demand an audience with Odin himself and lobbied for Ivar to be accepted into Valhalla on the grounds that he was an honorable warrior who had simply never met a man who could kill him on the battlefield. Odin was swayed by this logic and accepted Ivar into Valhalla. Ivar’s last command to his men before he passed on was for the necromancers to continue to provide this task for all Nordic leaders.
The necromancers returned to Midgard by resurrecting themselves and told their comrades of what they had done. The way that they had saved the soul of Ivar became celebrated among the Norse and resulted in a paradigm shift. Now, instead of being shunned as defilers of bodies, necromancers were celebrated as protectors of the soul. This trend continued even after Christianity displaced Norse Paganism with necromancers becoming inducted into the clergy as spiritual guides.
For many years, necromancers would be important members of the court for many royal and noble families. However, like many services available to the people in power during the Middle Ages and Renaissance, this was largely unavailable to the common peasants of the time. Attitudes towards this would later being to shift during the Age of Enlightenment with the stance that the common people were deserving of much of the same rights and respect as their rulers.
This came to a head resulting in major changes during the American Revolution. The ideals of this Revolution were firmly grounded in the Enlightenment movement and the Revolution came with the concept of doing away with the role of kings and nobles entirely. However, many of the leaders and especially military officers in the Continental Army were hesitant to do away with the spiritual protection that came with having necromancers attached to their armies.
The solution proposed was to have the necromancers provide this service to all members of the military. This way, the officers would benefit from the same protection they would expect in a European army but they could comply with the Enlightenment ideals that stated they held no special status above the men they led. This did require a significant increase in funding towards the necromancers employed by the Continental Army to improve both their quality and their numbers, but the program was a success. Gods of many afterlives quickly found themselves bombarded by paperwork from American necromancers. Some pantheons had to significantly increase their own legal offices to handle the new load.
The American dominance over necromancy and the legal processes in the afterlife remains to this day. The best cabal of necromancers in the world is unambiguously the United States JAG Corps. Several nations of the world reach out towards the JAG Corps for training their own necromancers. There are also more fully realized liches who work as lawyers for the United States DoD than are employed by the militaries of the rest of the world combined.
However, the United States is far from the only country that represents its troops with necromancers in the afterlife. Many other nations have copied the same approach and a few of the small but wealthy nations have offered the service to all of their citizens, military or civilian.
What sets the United States apart is that in addition to the legal advocacy in the afterlife, the JAG Corps has devoted a significant amount of effort into the other military applications of necromancy. Upon a soldier being KIA, they are offered an Honorable Discharge but are also offered the chance to reenlist. They can choose to have their body, their soul, or both continue to serve.
Bodies that are still in service are inducted into the Zombie Reserve Corps. A secret emergency force designed to quickly add manpower to a desperate situation. Some other countries do operate a similar force to some extent, but few match the scale and quality of the American force.
Souls that are still in service are bound to the earthly plane instead of entering the afterlife. They are often attached to intelligence agencies for their ability to scout locations and gather information unseen. There are nations that have the magical talent to enact countermeasures against them, but the fact remains that the nickname for CIA agents as “Spooks” was earned for a good reason and brings to mind literal ghost stories in some nations that have been opposed to the United States.
It is common for a soldier to devote their body without their soul so they can enter the afterlife while still serving. Less common but still frequent are soldiers who want to give their family an object to mourn and bury while still serving in a spiritual sense. What is rare is a soldier who offers both their body and soul. These soldiers are able to serve some very special roles. They do spend some time with intelligence services as a spirit, but ultimately how most of them are used is as a wight.
For this, a necromancer will bind their soul back to their body. Effectively, they will be a ghost who is possessing their own zombie. The resulting combination is physically much more robust than any typical soldier and even more so than the best of the normal zombies. They can also act as a focal point for necromancers controlling the rest of the zombie horde. So, they end up filling the role of NCOs and line officer ranks in the Zombie Reserve Corps while the necromancers are able to step back and take a broader command. It is this detail that functions as the trump card that makes the United States an unmatched powerhouse when it comes to necromantic warfare. Luckily, no conflict has necessitated the deployment of such methods, but the United States is ready if Romania were to try them.