Monstercrafting

Clean, traditional magic items must be forged at a Dragon Forge or lifted from the depths of the Underworld of Asalay - but those lands cursed by monsters find their own ways to make the best of the things that hunt them. These lands developed the art of Monstercrafting, the creation of rudimentary magic items from carefully combined bits of slain monsters. The introduction of new magical technologies - notably Alchemy - have allowed the craft to really flourish in recent centuries.
The heartlands of Monstercrafting is Stildane. Nowhere are the monsters more diverse, magical, and numerous than the Ederstone wastes. A few Desmians have tried to refine their own version of the craft for the Feywilds, but the Feywild monsters tend to be less fantastical and magical than their Stildanian counterparts. The introduction of Ederstone to the Feywilds has allowed the Desmian version of Monster-crafting to continue, but it remains a very niche industry. 
Other than Stildane, the big center of Monstercrafting is the Kingdom of Asalay. When Stildanians finally reached Asalay in significant numbers a few centuries ago, they brought the knowledge and principles of Monster-Crafting with them. As Asalay's monsters are more stable and consistent, they had to develop their own styles and specifics.

Utility

You cannot make a "+1" Weapon or Magic Stave or ring of power with any known Monster-Crafting recipe. Rather, the artform focuses on consumables such as potions, oils, salves, dusts, and glues. A few permanent magic items have been crafted this way, but these are rare and took generations of tinkering.
The most common products of monstercrafting are potions. Creating an immediately-acting and safe to drink potion requires a Healing Potion as a base - nothing else can magically distribute its effects through the body safely and instantly. All damage dealt to the drinker by the monstrous toxins is also healed immediately by the healing potion inside. It isn't enough to simply dump ground up monster dust in a healing potion, though - the monstrous ingredients must be carefully added during the brewing process. So an Alchemist should probably be involved in production. 
The most common permanent magic item is an Imbued Weapon, which is made from the magical claws and talons of powerful monsters. Great smiths can forge their weapons with the ash of magical claws and talons to give them this property as well, but it would take very condensed ash and a skilled smith. An Imbued Weapon is able to strike ethereal monsters and ignore damage reduction for non-magical weapons. Most warriors will not find them particularly different from normal weapons.
The most difficult consumable that is most recently developed is the spell-vessel: a monster part that can contain magical properties, exposed to repeated wizarding spells or other monster parts used for spell-like abilities. A spellcaster can draw power from a vessel rather than expend their own energy. In game terms, a spell scroll.

Access & Availability

Rare

Complexity

Extreme