Hemallurgy in the Cosmere RPG

How to use this controversial magic system and gain extra metallic arts.

In the Mistborn setting of the Cosmere RPG, there are 3 different magic system; allomancy, feruchemy and hemallurgy.

The ability to use allomancy and feruchemy is typically an inherited trait that some individuals possess. They are known as Metalborn and you can choose metallic arts to specialise in and use

However, hemallurgy does not follow a typical Metalborn path progression. Instead it can be gifted as a reward. In this article, I’ve looked at how hemallurgy works in the Cosmere RPG and how you might want to use it for your character.

Inquisitor sneaks up on a Mistborn: Brotherwise Games
Inquisitor sneaks up on a Mistborn: Brotherwise Games

Hemallurgy is the process of transferring invested arts like allomancy and feruchemy. It pierces an invested individual with a hemallurgic spike which then takes that investiture and can be transferred into another by inserting that hemallurgic spike into them.

Unfortunately, hemallurgy is fatal to the individual whose investiture is being taken (at least by currently known methods) making it quite a terrible form of obtaining investiture. Receiving a hemallurgic spike also damages your spiritweb making you more susceptible to the influence of a shard.

Knowledge of hemallurgy is rare, and the methodology is not widely known, making it an uncommon practice.

Gaining a hemallurgic spike is not easy. To start with, they’re rare. The other problem is usually, they’re already being used by someone else. And that someone else has been enhanced with a metallic art.

Not only that, but the knowledge of actually performing hemallurgy is unusal. You’ll somehow need to gain expertise in the method of performing hemallurgy or find someone willing to help you perform it themself. Something tells me a steel inquisitor isn’t just going to do this out of the kindness of their heart though.

Gaining hemallurgic spikes is locked behind tiers of play:

  • Tier 1: Able to gain the hemallurgist specialist expertise (this lets you actually perform hemallurgy)
  • Tier 2: Able to obtain hemallurgic spikes made of copper, iron, tin or zinc as a reward.
  • Tier 3: Able to obtain hemallurgic spikes made of bendalloy, brass bronze, cadmium, electrum, gold, pewter or steel as a reward.

The tiers differ because some spikes grant an increased attribute at tier 2, but the ones at tier 3 grant an actual allomantic or feruchemical art. I’m not quite sure why some metals don’t grant hemallurgic arts, and why those that do, can grant arts of other metals. I don’t think this is quite made clear, but it’s how the spikes work.

These tiers increase by 1 for every subsequent hemallurgic spike of the same metal. This means that a 2nd hemallurgic spike of iron would require you to be tier 3 and a 3rd would require you to be tier 4 and so on.

Considering that most hemallurgic spikes are going to already be in someone else, you’re probably going to have to remove them from an enemy. This is very much possible and isn’t too hard to manage, if you can get them into a state where you can remove their spike. This might mean killing, restraining or otherwise nullifying them while the removal is performed.

Zane, a Mistborn: Brotherwise Games
Zane, a Mistborn: Brotherwise Games

Here’s what you gain from a hemallurgic spike:

  • New power: If your spike grants an allomantic or feruchemical power, you gain that power as if you’d completed a Metalborn goal to unlock it. You can now choose talents from that talent tree when you level up. Hemallurgic spikes that can do this include:
    • Bendalloy
    • Brass
    • Bronze
    • Cadmium
    • Electrum
    • Gold
    • Pewter
    • Steel
  • Attribute increase: Other metals will grant an attribute increase instead. This is the case for:
    • Copper (intellect)
    • Iron (strength)
    • Tin (awareness)
    • Zinc (willpower)
  • Existing power: If you already possess the metallic art granted by that spike, you instead gain an additional rank in allomancy or feruchemy and this doesn’t count towards your maximum rank in that skill (so you can become more profound with your powers than other Metalborn).

Unfortunately, hemallurgy comes with drawbacks too, including:

  • Disrupted spiritweb: Your spiritual defense is reduced by 2 for each hemallurgic spike you’re using.
  • Subsequent spikes of the same metal: This gets even worse when you have another spike of the same metal. For these spikes, your spiritual defense reduces by 5.
  • Disorientation: At the start of each scene, if you’re using hemallurgic spikes and your spiritual defense is 9 or lower, you become disoriented until the end of the scene.
  • Influence of a shard: This isn’t necessarily bad, but many characters have viewed it as negative in the books. But if you have a hemallurgic spike, a shard can communicate with you directly and will likely try to manipulate you towards their will.
  • Succumbing to the influence of a shard: If you have 4 hemallurgic spikes or more, you become fully under the control of a shard and can no longer act as a PC. This means your character is now an NPC and you’ll need to roll up a new character.
Vin burning atium: Brotherwise Games
Vin burning atium: Brotherwise Games

Hemallurgy can be loads of fun, especially for players that like more risky and morally problematic gameplay. But like fireworks, you should absolutely only use it responsibly (if that’s even possible).

Don’t get 4 spikes

You should definitely not get 4 hemallurgic spikes. This effectively means the death of your character and you can no longer play them. They are now under the control of a shard (the GM) and you’ll need to roll a new character.

Technically, that 4th spike could be removed by the party, but who’s to say the GM will make this easy for you? Chances are, that shard is not going to want to give up their powerful new servant.

Spiritual defense may not be hugely important

When I assessed the Stormlight adversaries, I found that they very rarely tested against spiritual defense. This would mean that lowering it maybe isn’t that problematic. This might be different for Mistborn adversaries, but I found that it’s more often adversaries that need a better spiritual defense than PCs.

But don’t let spiritual defense get down to 9

Then this becomes a big problem as you’re always disoriented. This means no reactions, senses are obscured and disadvantage on perception tests. This is a big problem.

If you want enhanced metallic arts, take a metal you already possess the art for

The potential for 6 ranks in allomancy/feruchemy is quite good, but this option is best if it actually helps you achieve 6+.

Investing in presence and awareness

These are the attributes that relate to spiritual defense. If you want to take more hemallurgic spikes, you’ll need to make sure these are high enough that you won’t be disoriented.

Avoid spikes of the same metal

It’s not worth the -5 to spiritual defense and you’d need a spiritual defense of 17 minimum to prevent yourself getting disoriented, which is quite high and the positives rarely outweigh the negatives.

Hemallurgic spikes are only worth it if they complement existing capabilities

There are drawbacks to hemallurgic spikes so it’s only worth using them if they work well with your existing capabilities and you actually want to make use of those talents. It’s no good gaining a copper spike to enhance your intellect, if you’re a build that doesn’t really use intellect.


Hopefully you have a decent idea about the very controversial magic system of hemallurgy. Do you plan on integrating hemallurgy into your character build? Let me know in the comments below.

Published by Ben Lawrance

Ben is an experienced dungeon master and player who's been immersed in the D&D universe since he was a teenager over 20 years ago. Ben is the creator of Dungeon Mister and when he's not writing about D&D, Ben loves creating fiendish puzzles and devious dungeons for his players. He's an especially big fan of the Ravenloft and Dragonlance settings.

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