Necromancy

necromantic theory part 1: what actually is necromancy?
necromancy is any re-animation of formerly animate living matter. there's a lot of ways you can make this happen via magecraft, Royal magic (Prince/Court/Throne gifts and their demon/angel conjugates), or pillar magic. some involve souls, some don't. TENTATIVE: there may be an in-universe distinction between "true" (soul-using) and "false" (non-soul-using) necromancy, but practically, the boundaries between them might be blurrier than people assume.

true necromancers
anatomists are dr. frankenstein types. get real good at patchworking corpses together or restoring single corpses to working order, then finding the soul socket & summoning in a soul via alchemical methods or lightning or w/e. anatomists can’t really revive bodies in the field for immediate use, but they can make all kinds of wicked chimerical constructs with properties not seen in nature, and painstakingly rethread a body’s nerves to make it a better soul vessel, and and and. basically very advanced surgery-autopsy eventually lets you bring back the dead.

risen necromancers are undead & make use of the fact their souls are "naturally" loosely attached to get necromantic effects via long practice (effort magic). risen legionnaires can voluntarily fragment their soul into bits & animate temporary undead with them. can also bolster/heal other undead with soul fragments. risen soulcallers can turn their souls into doorways/ladders for other souls and make permanent undead by sticking souls back into the bodies they belong in. can also create temporary undead by just smacking any old soul in there but this sucks because they're attached to their own undead by a pulled-out thread of their souls (this is what gives them permanent command.)

fallen necromancers are living individuals who have managed to put themselves in a loose-souled state by getting reeeeeeally close to being dead. (NDEs through blood loss, drugs, starvation, etcetera. starvation and mortification of the flesh, especially while hanging out in mortuaries or graveyards, is the preferred route for most religiously inclined fallen necromancers.) once they're sitting on death's door they can then practice soul-manipulation the way the undead do but they're, like. weird to be around. grave shepherds are the fallen analogues to risen legionnaires, while spirit mediums are the fallen analogue to risen soulcallers.

demonhosts of souls have the Prince of Souls' Prince-gift and generally resemble soulcallers/spirit mediums but without having to be dead and/or creepy. except insofar as demonhosts are naturally creepy.

pillar warlocks who can superpose a living being with their dead self from an adjacent pillar (or vice versa -- dead with living) are known as deathshifters and their undead are just. incredibly effed up. in ways that i will figure out later LOL. ADDED: deathshifters work by superposing a person, LIVING OR DEAD, with an adjacent pillar version where that person is dead & under the necromancer's control. real bad.

timeline notes: anatomists may have been around for a long time because lbr people are going to do Weird Things With Corpses, but risen & fallen necromancers only showed up en masse(1) after the Unearthed started appearing since it was not at all obvious you could do that with a soul.

(1) an unknown but small number of Princes did develop necromancy as the Prince of Souls did, but they were eradicated fairly quickly because their necromancy was viscerally unpleasant (to say the least). the Prince of Souls survived long enough to become a Monarch in part because her necromancy seemed so natural and seamless, and was used so close to a person's death the reanimated individuals did not appear to be grotesquely or visibly undead. however, true resurrection--returning an individual to full, functional life after her soul has departed her body--is impossible on Nephele; anyone "resurrected" in this fashion is undead and subject to the limitations thereof, though some of the limitations can be overcome if the necromancy is done correctly and the body treated with exquisite care.

undoubtedly, effort magic necromancy was discovered prior to the advent of the King of Eyes, but it would be unbelievably rare and its practitioners (who are usually undead themselves) quickly extirpated wherever they cropped up. the Locust War marks the first widespread use of necromancy in warfare Nephele had ever seen.

there are certainly other varieties of true necromancers out there but these are the ones we know about.

false necromancers
puppeteers are as it says on the tin! not all mages with magecraft around puppetry can animate dead organic stuff well enough to get the necromancer label; generally the ones who do have done a lot of their practice up to gaining magecraft with bones, taxidermied animals (nope: chuck testa), etcetera.

courtiers of legends can animate anything that was once-living (though generally it works best with things you can draw with -- charcoal, blood) by pushing their soul into it and producing the illusion of life. more on the false necromancy side because it requires extended concentration to maintain versus risen legionnaires/grave shepherds who are ~similar but can create self-maintaining (if short-lived) undead via soul fragments. the Prince of Legends himself can outright make new people and it's unclear if that's weird necromancy or what.

fleshwarpers don't bother with superposing actual selves over anything they just use creepy pillar magic to force dead flesh into a semblance of life. it tends to mutate a bunch when they do this. it's like the worst possible claymation imaginable.

puppeteers have also been around forever but it's anywhere between incredibly gauche to incredibly illegal to use puppet-magecraft on parts of people, and most places don't like seeing you do it with dead animals either. courtiers of legends only appear in Legends-era.