Compounding

Compounding is a technique for using Allomancy to enhance Feruchemy. A person capable of Compounding is referred to as a Compounder.
== Mechanics ==
When a Metalborn has Allomantic and Feruchemical abilities in the same metal, they may store an attribute inside of a metalmind and then Allomantically burn the power. This gives a supercharged burst of the Feruchemical attribute, rather than the typical Allomantic ability. For example, a Twinborn with both abilities in iron can store weight briefly in a metalmind and then burn the metalmind to draw out an order of magnitude more weight than was originally stored (instead of receiving the usual Pulling ability associated with the Allomantic burning of iron). Both Sazed and Waxillium Ladrian suggest that the Feruchemical power withdrawn is multiplied tenfold, but it is unclear how accurate this number is. 
To understand the mechanics for this ability, one must first understand the differences between Allomancy and Feruchemy. Allomancy is considered an end-positive system, meaning power is drawn from an outside source--in this case, from Preservation. Feruchemy is an end-neutral system, with the power for the magic being drawn directly from the magic user--the amount of Investiture drawn out of a metalmind is equal to, and limited by, the amount of Investiture that was stored in the first place. In both cases, the type of metal acts as a focus, determining the form in which the magic manifests. When Compounding is performed, the nature of the Investiture already stored in the metalmind determines the form taken by the magic--thus Feruchemical attributes are released. However, because the Allomancy is fueled by Preservation, the amount of Investiture released is amplified. It is as if a previously hand-powered device were hooked up to an electrical cord to provide greater power output.
The power of Compounding is even greater than it may appear at first glance because the Feruchemical attributes being released may also be stored, rather than used, and the process repeated with a greater reserve of Investiture at the Compounder's disposal. Repeated cycles allow for exponential (and effectively infinite) access to Feruchemical attributes.
While Compounding typically refers to Allomancy enhancing Feruchemy, there is likely a way for Feruchemy to enhance Allomantic abilities as well.
== Limitations ==
Even for someone who knows it is possible, Compounding is not an intuitive ability, but rather takes time to learn. Hemalurgists also need to learn to overcome "Identity contamination" to be able to Compound, though it is unclear whether this has always been the case or if it is an additional restriction that originated after the Ascension of Harmony.
To perform Compounding, the metalminds themselves must be burned. Thus a person can only Compound only so long as a supply of metal is accessible for the purpose of producing more metalminds. These metalminds also must be small enough to swallow or insert into the body, such that they can be Allomantically burned. These restrictions effectively impose an upper limit on how much of a Feruchemical attribute a Compounder can draw on continuously.
Compounding is also only possible with a metalmind that is not "locked" by Spiritual Identity--that is, the metalmind must either have been created by the user themself or it must be "unkeyed". Any Allomancer is technically capable of Compounding--even without Feruchemical abilities--if the metalmind has been "unkeyed" by means of Feruchemical aluminum.
== Dangers ==
Compounding brass too vigorously could also result in overheating, leading to heatstroke and other heat related maladies, including death.
According to rumor, Miles Dagouter would constantly tap his metalminds for healing. Waxillium took this to confirm his suspicions that Compounding could be dangerous to stop once started--presumably because the Compounder's body comes to rely on the stores provided. This suggests that Compounding often leads to savanthood.
Steel Compounders, while unaffected by G forces, have an upper limit where air resistance and friction will burn them up and potentially kill them if they are not careful with their speed.
== History ==
The Lord Ruler used this ability extensively, as he was both Mistborn and a full Feruchemist, so he could Compound in every metal. He would age briefly to store youth in atium and then burn it to effectively live forever. He also used gold Compounding to heal very rapidly, leading to rumors that he survived flaying and decapitation. Compounding is also one potential reason the Lord Ruler persecuted Feruchemists so extensively--he did not want Feruchemists to mix with Allomancers and create more Compounders.
During the Final Empire, Steel Inquisitors were not taught how to Compound and usually did not have a combination of abilities that would allow for Compounding, though some Inquisitors may have figured it out. While the additional spikes they gained after the death of the Lord Ruler would have enabled them to Compound at least some metals, even with Ruin's help, they did not have time to learn how to do so before the Catacendre. However, Marsh, the sole Inquisitor still alive after the Catacendre, eventually learned to Compound and used a bag of atium taken from KanPaar to extend his lifespan just as the Lord Ruler had done.
Miles Dagouter also used gold Compounding to heal himself incredibly fast with an effectively limitless supply of health--hence his nickname, Miles Hundredlives.
== Notable Compounders ==
* Rashek
* Marsh (an atium Compounder)
* Miles Dagouter (a gold Compounder)
== Notes ==
category: Metallic Arts
category: Allomancy
category: Feruchemy
es:Composición