Is Necromancy in-universe?

[Enkidoh]

Right, Necromancy does exist but is considered utterly taboo socially and forbidden, for good reason, as it's not bringing the dead back to life at all, it's actually a form of summoning Voidsent, who end up inhabiting the corpse and turning it into a demon at worse, or at the very least a reanimated skeleton or zombie.

Ul'dah's sister city Sil'dih was destroyed due to a zombie apocalypse that was unleashed upon it due to a necromantic potion (I won't say anything more other than it's part of the ARR Hildibrand quests), so accordingly even mentioning necromancy in Ul'dah can get you into serious hot water there. And several dungeons also involve cleaning up the horrific results of stupid mages who had been messing around with necromancy (both versions of Tam-Tara Deepcroft, both versions of Haukke Manor).

And this was in 1.0 not ARR but Minfilia's father Warburton... was believed to have been revived from death using necromancy... but the scene in question was rather ambigious.