Butchering Monsters for Potions and Profit in Knave
Inevitably, players are going to want to harvest multiple parts from the same monster or create a potion from multiple monster parts or just to sell them; these extensions to the alchemy rules will address those desires.
The coin value of a creature in good condition corresponds to its level. In this document, we will use OSE XP values as the coin values of creatures. A whole monster in good condition is worth its XP in coins; each part harvested from it is worth the same. All may be pawned for half value assuming a buyer, as usual.
Butchering a monster for a part or its meat or hide has a base difficulty equal to its level. Multiple parts can be harvested from the same monster, with each additional part requiring a separate roll, but at +5 difficulty for each part applied to all of the rolls, as it becomes more difficult to harvest any part while not destroying another that will be harvested later. The parts to harvest must be declared in the order that they will be butchered prior to rolling. The remainder of the monster is ruined or discarded in the process, good for not much else than chum.
Alchemizing a monster part has a base difficulty equal to its level. Adding multiple parts has a difficulty equal to the sum of the parts' levels; additionally, increase the difficulty by +5 for each pairing of parts with opposing effects (eg cold+hot, incorporeality+hardness).
For example, a Giant Rattler is level 4 and worth 125 XP, and thus a corpse in good condition is worth 125 coins and each part harvested from it is worth 125 coins. Harvesting the skin, venom glands and rattler from one of the snakes would require three rolls, each with difficulty 14 (+4 for its level, +10 for three parts).
Now, suppose we wish to create a potion of Poisonous Mist Form from the Rattler's venom sacks and Wraith essence. Both creatures are level 4, and there is nothing fundamentally polarizing about the effects we want to create, and so the difficulty to create the potion is 8.