I understand that when atium is used as a Feruchemical metal, it stores age. In that way, as long as there is atium with a charge stored up, you can halt yourself from aging.

However, where was the Lord Ruler able to get an essentially infinite charge so that he could keep this up indefinitely?

I know the first book attempted to explain how this worked, but I didn't really follow what was going on. Was there some way that Allomancy mixed with Feruchemy to make this possible?

  • To the editor: Gold stores health. Atium stores age.
    – StrixVaria
    Feb 5, 2013 at 12:12

5 Answers 5


Feruchemy revolves around an equilibrium: you can only get out of a metal what you put in to it, and after you're done everything is back in its natural state


Because Feruchemy is a "natural" art, a balance of Preservation and Ruin.

Allomancy does not have an equilibrium: you can get things out of a metal that you didn't put in to it, and at the end the metal is cleanly burned away and the energy is out in the world (extra kinetic energy from steel, for instance).


Because Allomancy is an art of Preservation, the power of creation and sustenance. The metals are burned to fuel the creation of allomantic effects, and IIRC it's even stated that this is a net-positive reaction.

Now, for most Feruchemists, storing age is zero-sum; you can be a bit younger, in exchange for being a bit older.

However, the Lord Ruler was able to perform both Feruchemy and Allomancy at the same time. This created a synergistic effect known in the later books as "Compounding", which pushed him out of the natural Feruchemical equilibrium and towards youth.

In fact, he would have been able to use any feruchemical power in a net-positive manner, by both storing the attribute in a metal and then later allomantically burning the metal while feruchemically releasing the attribute. For instance, this is almost certainly how he managed to heal incredibly quickly: he stored his health in gold and then burned it later.

And as related a side note about a third art, since it's aesthetically related:

Steel Inquisitors, Koloss and Kandra are the results of Hemalurgy, which also has no equilibrium - it's based on the powers of Ruin, so it's a net-negative reaction. Koloss, for instance, have the strength of multiple people but the intelligence of none of them.


The Lord Ruler uses a trick known as "Compounding", which can be used by anyone who is both an allomancer and a feruchemist (like the Lord Ruler), or by a twinborn, someone who can use one metal as both a feruchemist and a misting.

When you use feruchemy, you can only use what you have previously stored in your metalminds. For each day you'd want to spend as a 20 year old when you are in fact 100 years old, you'd need to spend a day as a 100 year old while you were 20 (or something equivalent, mind you). Feruchemy is limited by the energy that is available to its user. As such, one could not attain immortality that way.

Allomancy, on the other hand, uses the metal as a power source. Each metal is associated with a specific ability and, once you start burning that metal, the energy of the metal itself fuels your powers. But, like any fire, your fuel eventually runs out. That is the limiting factor of allomancy: one cannot extract more energy than what is contained in the metals.

However, when one can use both feruchemy and allomancy, interresting things become possible. For instance, you can use your allomancy to burn away your metalminds, using the energy from the metal to amplify what was stored in it. This is what is called compounding. We do not really know the magnitude of this amplification, but it is said throughout the series that the Lord Ruler goes out of sight for a few days every once in a while. Presumably, this is so he can store youth in a metalmind (Vin even confronts him at one such moment). Since the Lord Ruler can extract more youth than what he had stored by using compounding, he can break the balance of traditionnal feruchemy and live eternally.

  • Near-eternally, but close enough as to make the difference academic. 1000 years is pretty immortal to use 80-120 years-ers!
    – rsegal
    Feb 5, 2013 at 5:55
  • "We do not really know the magnitude of this amplification" - that seems to be what makes one a stronger/weaker mistborn Dec 1, 2013 at 3:12

Feruchemy only allows to take back exactly as much power as you put into the metal yourself. Allomancy burns the power of the metal itself, you don't put anything of your own into the metal before, unlike feruchemy. But Allomancy doesn't have access to the same abilities as feruchemy, there is no allomantic metal that allows to prolong your life.

There is one scene in Mistborn where Vin tries to burn one of Sazed's feruchemical metals, and she isn't able to use it. Only the one that originally stored a specific attribute in a metal can use it again.

The Lord Ruler, being an allomancer and a feruchemist, was able to store an attribute such as age in a metal, and then could burn the metal to get out more than he stored in it. While feruchemy is balanced, and you can't draw more from the metal than you put in, allomancy burns the power within that metal and is not subject to that limitation. That was the reason why he tried hard to eradicate feruchemistry out of the Terris people, to prevent anyone gaining access to the same power he has, by being an allomancer and a feruchemist.

  • Can you go into a little more detail on exactly what he was doing in order to preserve his life infinitely, though?
    – StrixVaria
    Feb 4, 2013 at 22:07
  • As far as I understand it, burning a metal as an allomancer is simply amplifying the amount of youth he put into the metal as a feruchemist. That is the trick to get the infinite youth.
    – user496
    Feb 4, 2013 at 22:09

Expanding on what Mad Scientist said, if the person in question also burns (and flares!) duralumin while doing this process, it will become extremely more efficient and the long-term use of atium would decline as a result. Furthermore if you use atium, hemalurgic spikes can steal any property, whether allomantic, feruchemical or even just a natural property of being a human, any person willing to undergo this horrific transformation would find their allomantic hemalurgic feruchemical spikes store age far more efficiently than normal and were they to replace non-vital spikes once in a while and burn them, they would find it to be extremely efficient, even more so if they are again burning duralumin on the side. The extreme and unnatural (even by their standards) acquisition of youth would be so drastic that they would need to already be storing youth away in their new spikes, of which they could access in a pinch of trouble.

If we assume atium spikes are 15% more efficient storage of feruchemical powers and that burning duralumin in this process increases output power by 50%, we can estimate that even by these generously understated values would have a significant impact. If we assume that the lord ruler increased his life span from ~80 to ~1040, which is also significantly understated (increasing his estimated life span to 13x normal) and even if we add up the increased efficiency incorrectly, we can downplay it to 75% more efficient overall.

This means that if the Lord Ruler was smart enough, he could have lived at very least 23x the normal human lifespan, resulting in an absolute minimum of 1800 years and I haven't seen anything as of yet saying the Lord Ruler's neat little trick was running short by its own merit.

Thinking realistically, he could have lived to 4000 years old and even greater.


At the end of the first book, right before he is killed, it is mentioned that the Lord Ruler looks tired. I believe fatigue is mentioned a few times, even when he is young appearing. Notice that the Well of Ascension refills one year after the Lord Ruler's death. I suspect his plan was to use the power at the Well to remake the world again (v. 2.0 if you will), and at the same time remake his own body over again. Unfortunately, Ruin knew that he would get tired and sloppy late in the cycle, and took advantage by providing Kelsier and Vin the opportunity to remove the Lord Ruler.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.