Biothaumaturgy

Arcane magic, save for certain rare circumstances, can only be used by those with a connection to the primordials. Since the deities severed the ties between the Soulborn and the primordials, that means that, at the very least, the culled races no longer possess the affinities necessary to channel such magics. Likewise, creating true magic items is an incredibly costly process, both in terms of time and resources, leaving the practice all but relegated to ancient history. That’s where biothaumaturgy comes in.
Biothaumaturgy is a practice somewhere between science and the occult, that was developed in order to bypass the limitations regarding the use of arcane magics and the crafting of magic items. A gross simplification of the process would be to say that it involves creating stable biothaumaturgical constructs from the preserved organs and parts of monsters. These constructs are then either grafted onto the bodies of Soulborn, colloquially called grafts, or are used as standalone tools, referred to as vestiges. Biothaumaturgy allows for a nearly infinite range of creations, ranging from the crafting of living swords to the transplantation of beholders’ eyes. The specifics, however, are much more complicated.
Of special note are the hearts of monsters - these essential organs are exclusively transplanted into the chests of prospective arcane spellcasters, replacing their own hearts and gifting them with the unnatural ability to channel arcane magics.
Biothaumaturgical grafting is harrying. Each step of the process is expensive and fraught with danger, potentially leading to insanity, dismemberment, or worse. While carrying a weapon or wearing armor made from a monster is virtually the same as carrying a true magic item, it is when monster parts are grafted onto the body of a subject that the risks of this practice become apparent. Monster parts are infected with the essence of the primordials themselves and subjects who overload their body with grafts risk becoming increasingly tainted by their foul miasma. As a result, overuse of biothaumaturgical grafts can lead to insanity, mutation, and even death. In the worst cases of biothaumaturgical taint, the subjects devolve into chimeric monsters in service to the primordials; the Broken are prime examples of this fate.
Due to the inherent dangers of biothaumaturgy, the art is jealously guarded by those who practice it and heavily legislated and monitored by the nations in which it is found, though more so regarding biothaumaturgical grafting than crafting. Apothecaries, the primary practitioners of biothaumaturgical crafting and grafting, can spend a decade or more in training (usually on animals and prisoners) before being licensed to practice openly. That being said, biothaumaturgy is one of the cornerstones of civilization in modern Edras and as such, its practice is widespread and well tolerated by the populaces of most nations. Markets filled with monster butchers and freelance apothecaries can be found in the largest cities of Edras and even the snootiest of nobles are known to indulge in a graft or two.