Biothaumaturgy

Harvesting Monster Parts

In order to successfully identify and claim the various useful parts of a monster’s body, a character must make an Ability Check with the Skill that matches the monster they are harvesting plus whichever Ability fits the job (usually Dexterity or Strength). The roll is made with Advantage if the character is Proficient in the Chirurgeon’s Kit tool.

• History: Giants, Humanoids
• Arcana: Aberrations, Constructs, Elementals, Oozes
• Nature: Beasts, Dragons, Monstrosities, Plants
• Religion: Celestials, Fey, Fiends, Undead

The following chart shows how many times this harvesting roll may be attempted and how long each attempt takes, depending on the size of the creature. The Time Per Attempt can be halved if the character has help from a number of assistants equal to those shown in the “Assistants Required” column, who are proficient in either the monster harvesting Skill used or in the Chirurgeon’s Kit.

Creature Size	Harvesting Attempts	Time Per Attempt	Assistants Required
Tiny	1	2 minutes	N/A
Small	1	10 minutes	N/A
Medium	1	30 minutes	1
Large	2	1 hour	1
Huge	3	4 hours	3
Gargantuan	5	1 day	10

A success on this roll means that the character is able to harvest a random number of a single type of monster part determined by the GM rolling on the monster’s harvest table. For each multiple of 5 that the roll exceeds the target DC, the character is able to harvest another random number of a single type of monster part. The character may choose to make their roll at a higher DC to target specific monster parts, rather than rolling randomly, by increasing the DC by 5 and forfeiting any extra monster parts gained by beating the DC by multiples of 5. If the character chooses to target a specific monster part and succeeds, they gain double the number of parts from the roll (if possible). Monster parts can run out; for example, if you have retrieved 20 claws from a hellhound, it doesn’t have anymore to give.

Monster CR Range	Equivalent Magic Item Level	Taint	DCs	Cost
0-5	Common	1	10	(1d6+2)*10gp
6-10	Uncommon	2	15	(1d6+2)*50gp
11-15	Rare	3	15	(1d6+2)*500gp
16-20	Very Rare	5	20	(1d6+2)*5,000gp
21-25	Legendary	7	25	(1d6+2)*50,000gp
26+	Artifact	10	30	1,000,000+gp

Attunement & Taint

While biothaumaturgical magic items that are held or worn can be attuned to, much like a true magic item, biothaumaturgical grafts never require attunement. Instead, grafts add to a character's total Taint level based on their relative power according to the chart above. A character can fight off the infection of the primordials’ essence as long as their total Taint is no higher than 10 + their Proficiency modifier. Once this limit is reached, the character devolves into a lunatic monster that serves the will of the primordials and becomes an NPC. There are other effects of Taint, which are determined by the chart below.

Taint	Effect
Less than 3	None
3 to 6	Gain a Minor Madness
7 to 10	Gain a Minor Mutation
11 to 14	Gain a Major Mutation
Greater than 14	Gain a Major Madness

Minor Madnesses: Phobias, addictions, disorders, etc. Examples - Arachnophobia, Depression or Addiction to Alcohol.
Major Madnesses: Reality altering delusions and hallucinations. Examples - I am infested with sentient fungal blooms, I am starving and must consume everything that I can, or I believe that other humanoids no longer have faces and have been replaced with aberrations from beyond the stars.
Minor Mutations: Disturbing but purely cosmetic mutations. Examples - My eyes drip ichor instead of tears or my skin has turned to scales.
Major Mutations: Horrifying and debilitating mutations. Examples - My eyes have fallen out and been replaced with bloody tentacles that I “taste” the world with to see or my limbs all bend digitigrade now and are malformed.

A New Tool Proficiency

The skill possessed by all Apothecaries that allows them to graft monster parts onto Soulborn is called Chirurgy and is governed by the use of the new Tool Proficiency called a Chirurgeon’s Kit(100 gp). The kit comes complete with anesthetic herbs, steel surgical implements, thread, and various salves and glowing liquids. The Chirurgeon’s Kit Tool Proficiency is most often paired with Intelligence and Dexterity.

The Process

The process for retrieving and attaching a monster graft can be found below:

1. Choose a monster of appropriate type and CR to hunt. No additional rolls here.
2. Hunt and kill said monster. No additional rolls here.
3. Harvest the monster parts. Roll against the monster’s biothaumaturgy DC to harvest parts.
4. Preserve the desired monster part via magic or alchemy. Monster parts are automatically preserved for transport by the casting of Gentle Repose or the use of a Biothaumaturgical Preservation Kit (100gp). Monster parts can also be preserved for transport through an Intelligence (Alchemy) check using the DCs in the above chart. Failure means that the part was improperly preserved and thus the graft preparation or crafting roll is at Disadvantage. Failure by 5 or more means the part has not been preserved correctly and is useless.
5. Take the monster graft to a trained Apothecary. Apothecaries usually charge a fee equal to the Cost in the above chart. At this point the Apothecary will either turn the monster part into an item to be held/worn (use the Magic Item Crafting House Rules) or into a graft (use the steps below).
6. The Apothecary will prepare the graft for transplantation. Monster grafts are prepared for transplantation through an Intelligence (Chirurgeon’s Kit) check using the DCs in the above chart. Failure means that the graft is able to be prepared but the implantation roll will be at Disadvantage. Failure by 5 or more means the part cannot be prepared for transplantation and must be thrown out.
7. Then the graft will be surgically attached to the subject by the Apothecary. The monster grafts are surgically attached to the subject through a Dexterity (Chirurgeon’s Kit) check using the DCs in the above chart. Failure deals the CR of the graft in d8s to the subject due to massive hemorrhaging and causes a Lingering Injury. Failure by 5 or more causes a heart attack which immediately drops the subject to 0 HP and causes a permanent malfunction of the graft.
8. Lastly, the Apothecary will animate the graft by spiritually linking it to the subject’s soul. This is done with a simple prayer to the Brisingelion asking for protection for the soul of the subject from the horrors of the primordials and for wisdom in using their new gifts; this is a minor ritual, called the Ritual of Transformation, that can be completed by any Ritual Caster and requires no roll. The subject must then make a Saving Throw using their spellcasting ability or constitution (whichever save is higher) at a DC equal to the CR of the graft. Failure saps the life force of the subject dealing 1 level of Exhaustion and gives a Short-Term Madness. Failure by 5 or more deals 3 levels of Exhaustion and gives a Long-Term Madness. Failure by 10 or more deals 5 levels of Exhaustion and gives an Indefinite Madness. These Exhaustion levels cannot be removed via magic, only through rest.

Example Biothaumaturgical Magic Items

Spinal Greatsword: A polished, ivory greatsword made from the spine and tail of a Bone Devil. Veins curl around it and pulse with viscera. It adds 1d6 poison damage to attacks and can extend out to a 15 foot reach once per short rest. This is about the power level of an uncommon magical item, so the Bone Devil would have have to be CR 6-10, the part would cost 250G if you bought it, the work to craft it by an apothecary would be 250G, and the DCs for its crafting rolls would be 10. Because it is a carried item, it would require Attunement, but would not add to your Taint. A grafted version of this item, where the sword was stored in your back or in your arm, would not require Attunement, but would add 2 Taint to your total.
Monster Heart: The beating heart (core, center, whatever) of a monster. This is the one biothaumaturgical magic item that all arcane casters require. It allows for the casting of arcane magic, usually flavored by the type of monster it came from. This is a common level magic item in cost and DC, though it could have come from any monster regardless of CR. Because it is a grafted part, it would add Taint to your character. In the case of a common magic item level part like this it would add 1 Taint, but as a special rule Monster Hearts instead subtract 1 Taint.
An Alhoon’s Withered Hand: The withered hand of an albino Mindflayer who dabbled in the arcane and the secrets of immortality. Grafted in place of your hand, this biothaumaturgical item, other than being a functioning hand, allows you to fire Magic Missiles at will. This hand has 7 Charges. You can use an action to expend 1 or more of its Charges to cast the Magic Missile spell from it. For 1 charge, you cast the 1st-level version of the spell. You can increase the spell slot level by one for each additional charge you expend. The hand regains 1d6 + 1 expended Charges daily at dawn. This is about the power level of an uncommon magical item, so the Alhoon would have have to be at least CR 6-10, the part would cost 250G if you bought it, the work to craft it by an apothecary would be 250G, and the DCs for its crafting rolls would be 10. Because it is a grafted item, it would not require Attunement, but would add 2 Taint to your total.