Somehow, the practitioners of death art managed to name it as such, even though it shouldn't be called an "art" at all. It is perhaps rightly considered forbidden by the few former Melokai I have managed to talk to. Indeed, the horrors of it are such that I will keep this entry short.
Death art is the practice of magically controlling souls, and is at least somewhat connected to Habeth (consensually or no). When a humanoid dies, its soul walks a path to join the gods in the heavens. Somehow, death art practitioners have learned how to bind one of these souls to our mortal realm, before or after it has walked the path. These souls are often rightfully angry at having been detained from their rest, and so the resulting creations are usually violent - and unkillable by normal means.
The more powerful a death art practitioner (or "necromancer" as they call themselves), the older a soul they can bring back to the mortal world. The longer a soul has been in heaven, the more filled with divine energy, and therefore the more powerful… but also more insane.
Somehow, these diabolical magicians are able to bind these creatures to their wills, treating them as slaves.