Sentient beings, such as elves, humans, orcs, dwarves, etc., all contain mana that can be used to perform spells, or alternitively, can be stripped for the purpose of being used to create items or perform magical rituals. This energy exists within the body of an individual and saturates various parts of the physical form, such as organs, skin, and bones. Species contain different kinds of mana which range in colors all over the spectrum, such as green, red, and blue. Each mana type holds certain properties, and can be mixed and matched with each other to produce specific magical effects. Sacrificial priests from the Daaevite Empire sacrifice thousands of captives a year to their deity. Victims are ritualistically murdered on an altar, after which their remains are repurposed for other uses. Organs, bones, and skin are removed, ground up, placed in jars with labels identifying what species they belonged to, and stored to be used as materials in future magical rituals.

Even though these materials made from different species can be used together for spells, they must be stored separately and kept apart while stored before they are ready to be mixed. Different types of mana from the samples of various individuals can blend and leak into each other, corrupting and destroying entire batches completely and rendering them useless. To prevent this, certain procedures are put in place as precautions.

  1. Samples taken from different beings are stored in reinforced containers and organized according to species type.
  2. Containers are kept on separate shelves on separate floors with others of their type so that there is no ability for mana of different species to come into contact.
  3. Items used in conjunction with these samples are regularly sterilized and washed.
  4. Priests who are responsible for maintaining this equipment must wash hands regularly. Those who are unable to follow instructions become part of the collection they were once responsible for maintain.

Because of the safety checks and the punishments associated with not following them, priests tend to follow these procedures to the letter. Despite this, cross-contamination is an ongoing problem for all mages in society in general. The consequences of this can be disastrous for the ritual and the practitioner, with unpredictable effects. Sometimes spells do not work, while others simply explode in the face of the individual and causing death. How can this be the case when all of these procedures have been followed?

  • $\begingroup$ Why not simply declare a property of this magic system that all mana decays and becomes less pure over time? $\endgroup$
    – Daron
    Dec 11, 2021 at 16:08

6 Answers 6


One of the most obvious source of cross contamination is hybridization. Some of these races (humans and orcs, especially) are well known to produce occasional hybrids with a range of other races, and those hybrids will contain a mixture of the mana qualities of their parents (or more distant ancestors). In practice, this can (for instance) lead to strain of elves who have a single half-elf, half-human ancestor, thousands of years ago, (which might be only 2-3 generations for elves) making all elves of that line useless for this "stripping" process.

Given that orcs are well known for hybridizing with almost anything, humans seem interfertile with most fantasy races, and it's quite possible dwarves and gnomes might be, um, closer than they appear, it makes careful breed management and pedigree records of critical importance for those who might wish to strip these races for their magical ingredient potential -- not to mention very effective (and sterile) guards for the breeding farms.


Garbage in, garbage out:

The problem isn't in the processing & purification, but the fact that most of the sacrifices are of beings obtained "in the wild," so-to-speak, not taken from individuals specifically raised in captivity separate from any source of contamination.

While mana can saturate tissues, every being takes up random bits of mana in the form of mana from plants they eat that grew on the feces of humans, bugs they swallow that bit orcs, or even dust blown off of the graves of thousand-years-dead elves.

A living being has their own mana, and like a lot of life, they keep contamination efficiently contained in the liver, cysts, vesicles or other structures where the body can isolate contaminants it can't use. The moment you kill a being, the mana is no longer controlled and structured to keep the contaminants in place. A FRESH troll body might give you the effect you want, but within hours, decay starts and those mana toxins begin spreading, contaminating the tissues with random bits of mana collected over a lifetime of living a random life in the wild.

To combat this problem, you might need to follow any of a number of steps to prevent this:

  1. Children: Children have contacted fewer random sources of mana in their lives. The "toxic" mana simply hasn't accumulated.
  2. Slaves: Species raised in captivity with pure foods, clean air and no exposure to other species will be clean of alternative mana.
  3. Undead: Providing alternate life to the tissues (or whole individuals) will prevent the decay and release of the mana toxins, so the tissues are still effectively "fresh" until ready to use. This may have unintended consequences.

Unfortunately, the life experience, exposure to outsiders, and general health of the individuals will all contribute to the variable quality of the parts harvested. People from isolated islands may have no contamination from other species, or they may be merchants and travelers, or readily have access to foreign foods and products with lots of contaminants. The empire should try to discourage people from traveling, eating unfamiliar things, or even speaking to foreigners.

  • Well, except the one that arrives in a haz-mat suit with a bunch of canopic jars and a sharp knife...

Mana decay

Without the processes of a living body and soul to regulate and regenerate the mana in the individual, natural thaumaturgic interaction of the mana with the (now dead) matter containing it, the material of the container it's stored within, the surrounding environment (e.g. temperature/humidity; yes, even in a sealed container; magic is not so easily contained), and even with high densities of other mana of the same type, can cause decay of the mana into other unwanted forms of mana. The mechanics and theory of this was not understood until centuries after the practice began and so the practitioners of the era were mystified as to why some stored materials remained good for a very long period of time and others went "off" and caused a spell malfunction even after only a short period of time. Until that knowledge was developed, spell malfunctions among practitioners was more or less a routine occurrence.


Chemistry has this issue.

This is a huge problem/concern in chemistry. How do you know your reagent is what you think it is? Granted some of these are just contamination not cross contamination.

But how ever your reagent is contaminated predictable results are much less certain with any containerization.

Contamination paths

Just to start with forms of contamination.

  • Some might react with some portion of air.
  • Some will react with containers depending on compatibility.
  • Some might start out as pure X but will change to equilibrium state. EG:perhaps 94.5% X 5% Y .5%Z
  • Maybe thaumic(magic) radiation is a thing/problem. Perhaps the thaumic radiation of stored dragon causes some nearby reagents to transmute.
  • Some labs will cut corners. It's not 100% green mana. It's 75% green mana plus filler.
  • People make mistakes (side note ending careers of highly trained people because of a mistakes is a very bad idea.)
  • Sabotage protestors, enemy state etc.
  • Many/most ingredients require exponential cost for each nine that is added on to the 99.9% pure. So practically speaking some reagents will always be contaminated because you can get 99.8% pure for \$10/Kg but 99.99% pure will cost \$10000/Kg. With perhaps it remaining that purity only if used within two weeks.
  • Poor documentation, Mixed in elbow grease of elf when it should have been brownie, labeled as brownie says faded label.

More specifically able to cause cross contamination:

  • Some are volatile(dissolve in air) which can then mix with other nearby reagents depending on storage.
  • Improper cleaning of containers used in reactions. This reagent you can clean with water, this one have to clean with benzene, this one needs dragon tears mixed with drop of pixie essence etc.
  • Impossible to clean issues. Micro cracks in stir rods and other equipment that hold trace amounts of previous reactions.
  • Some might decompose over time. E.G red mana decomposes into blue mana + something. Rate increases when exposed to some catalyst.
  • Perhaps some or many sets of ingredients are in equilibrium with each other. So to keep red mana from changing into blue mana it has to be kept at high pressure or with an acidic buffer.

Its a process.

Many of these things will eventually be discovered, understood and have the process of handling altered to suit. As procedures improve, this will have knock on affects of requiring other procedures to improve. Which will then require other procedures to improve etc. That is exactly like chemistry.


Poor Air Filtration

You mentioned that they ground the bones, skin and organs up, implying that it's a powder. Unless they properly understood air filtering and had a way to create a clean room of sorts, it'd be fairly easy for particulates to enter the air. They would then be carried through the air and could enter other rooms or locations. Say in one room, a group of mages where working with some mana. Without proper filtering, particulates could make it into another room where a different group of mages where working, thus contaminating the other mana.

Of course, if the mages understood this then they might be able to avoid it. Create a magic clean room or something. Also not sure if there would be enough particulates in the air to completely mess up other batches of mana.


Those precautions look very similar to those in place for handling radioactive material, and also in the case of radioactive materials sometimes contamination happens. How?

Well, people are in a rush to meet quota and they start cutting corners, doing things like disregarding operational procedures or not following the proper review and approval process for new procedures.

Something similar can happen in your case. There will be some high poppy pushing for meeting quotas and deadlines, and some procedures will be skipped, with the result that incidents will happen.


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