Mark_Confidant

In northern Scadrial without any Hemalurgy schenanegans sure. Southern Scadrian medallions are unkeyed Allomancy or Feruchemy Necrosilminds, so at some point relatively close to Bands of Mourning any Misting or Ferring is going to have pretty easy access to compounding in their respective metal. My guess is that aluminum ends up being the currency de rigueur in this situation. It's much more useful than gold or silver, but about as common as iron. Poorer people want small denomination coins that are unstealable by coinshots and lurchers, but richer people still see gold as a status symbol. Not to mention there's bonus status in managing to hold onto money that any old misting can snatch.

I'd bet a nickel this is a combination of the spikes punching holes in the spiritweb and the jumbles of Identity still on the spikes turning a multi spiker into a big soup of conflicting Identities. Also, while we're on the subject of metal true bodies, why Aluminum? You could have any compounder of a cheaper metal just turn each bone into a 'Month of X trait' metalmind and any sub Lord Ruler allomancer ain't gonna be able to do any pushing, and even the Lord Ruler wouldn't have the easiest time shoving those lumps. I'd imagine that Steel compounders would be the most in demand for this, assuming allomantic steel isn't so high carbon that it's brittle, and that Copper compounders would provide the cheapest, because they can very quickly do a Smellmind Sightmind and Hearingmind all at once (also it's funny to think of your bones being this random jumble of Senseminds). Also, if you get into unsealed metalminds or Kandra with feruchemy spikes it might be possible to have a kindra with either a load of storage of one trait in their bones or a jumble of different traits and a Necrosilmind to give them the Feruchemy necessary to tap it. Although in that case the Necrosilmind bone of their true body would be extremely important to keep inside them, as any attacker who can knock it out in one blow would essentially disable your poor-man's Full Feruchemist Kandra.

I'm going to go through this bulletpoint-y because I think it's probably the most legible way to reply here. If it comes off terse, I'm not trying to be. The power you'd be getting from the spike is precisely what the spike contains. If I tap a strength spike in this way, I'm taking out some of the spiritweb in the spike, which is the spiritweb that codes to strength. Admittedly, that chunk if spiritweb isn't itself strength, in the same way that a factory that makes shoes isn't itself a shoe, or in that a blueprint for the plumbing of a building isn't that plumbing, but the physical body is already really adept at using the spiritweb to get whatever traits the spiritweb tells them to have. Besides that, we already know from Compounding that it's possible to have metallic interactions that involve some magic becoming some other magic. Preservation's fueling of Allomancy 'should' only fuel Allomantic abilities, but a Feruchemically charged piece of metal overrides the instructions to instead have Preservation fuel the trait that's Feruchemically stored. Turning the chunk of spiritweb into a format that Feruchemy can use for power might just be one of those magical interactions. Moreover, it's an interaction that Ruin would want Hemalurgy to have, because Hemalurgy destroys some energy, and Ruin wants to see things destroyed. Saying "you can make this chunk of spiritweb accessible and useful in a way it never is during a person's ordinary lifetime, at the expense of permanently losing some spiritweb" is exactly the sort of interaction Ruin would prefer his magic system to provide when he designed it. It is the exact power the spike stole, but in a format that's much more usable. Consider this: when a person dies, regardless of their age, their spirit still sticks around for roughly the same time unless some other Investiture junk is happening. That means that, despite drawing strength from your spiritweb for your entire life, your spiritweb still has basically the same amount of strength in it. Strength is probably a bad example because it's confounded slightly by age screwing stuff up (maybe physically screwing up your body in a way that makes accessing your strength portion of your spiritweb harder? I dunno), so let's continue this bit using luck as our example. So you have more luck than you can use up in a lifetime, or your luck segment of your spiritweb makes luck. If it's the former, you just are getting however many lifetimes worth of luck is in that spiritweb. If it's the latter, you're destructively pushing the spirtweb into overdrive, or you're pulling that slice of spiritweb into yourself in a way that Hemalurgy or Feruchemy or your body can magically convert directly into luck. I worry we might be talking past each other a bit. To be clear, getting that burst of strength from tapping a strength spike at the expense of expending the spike is exactly what I'm talking about. I think that would be preferable because of just how much power is accessible there. So, a ferring+misting compounder can get, let's say, like 10x the energy stored in a metalmind when they burn it completely. That energy takes up space, so they're limited by how quickly they can burn metal. Let's say they can flare metal such that they consume a metalmind at 100x the rate they spent time filling it. In other words, a metalmind that took 1 hour to fully fill would take 36 seconds to burn. That means that continually burning metalminds at their maximum speed, they could store 1000 seconds worth of strength per second of real time. At a 6 months of nonstop storage, they would have 500 years worth of strength. By contrast, let's talk about the average human lifetime. Maybe 50 years on Scadrial, because the Lord Ruler is mean and everything is sad. 50 years worth of living doesn't noticeably affect the investiture inherent in a person's spiritweb. What's the maximum portion of a spiritweb that a living, uninvested person has used up in this situation? For sake of argument, let's say 10 percent. So, in other words, their spiritweb starts off with 500 years worth of whatever trait in it. Obviously spiking that bit of spiritweb you would lose some portion of it, but that means that with a single spike used a single time on a single person you would have access to what the most broken magic synergy we know of can do in 6 months of nonstop work. Like, the Lord Ruler can probably punch a building apart on a whim, but what does hundreds of years worth of power used in the span of seconds look like? Punching that building so hard chunks of it leave orbit? Sure, you'd definitely die, but that's partially because strength is a crappy thing to tap a lot of. Imagine 10 lifetimes worth of luck spent in a single second.

To be clear here, the spike in question is specifically from someone with no identity. Whether this is from them Feruchemically depositing all of their Identity while being spiked, from having their Identity spiked out (and surviving) before a second spike stabs out whatever the second trait stolen is, or through some unknown process of manipulating Identity we haven't seen yet.

Three reasons: two are kinda metagamey, and one that's more based on my understanding of the magic systems in general. Metagamey #1: To put it frankly, Sanderson has been astonishingly scarce about hemalurgy/feruchemy synergies. You'll notice that for the "what if an allomancer tapped a spike or a feruchemist tapped one" question he specifically answers the allomancer one. To me, that implies that he thinks this synergy will be important to the story in the future. Metagamey #2: Being able to use spikes outside of your body isn't a particularly useful or impressive magical synergy, doubly so because Hemalurgic spikes decay outside of the body. The most useful thing you can do with that involves a third magic system, and something like having a soulcaster or some sort of blood making fabrial constantly refresh blood so that your external spike doesn't decay and you have a readily accessible piece of soul to use without making your spiritweb more vulnerable seems underwhelming to me. Additionally, it seems to me like the soul-gene-splicing effect of burning a spike already does what a lot of people think tapping a spike would do, namely give you safe access to that chunk of spiritweb without putting your own spiritweb in danger of influence. There are some questions to be answered, like whether it's literally 'splicing' in the sense of trashing whatever portion of your spiritweb would code to that trait and replacing it with the bit in the spike or something more additive than that, but it still seems doable to amass power with that. So, given that it's something Sandy Brandy thinks is going to be important, and it's something not covered by another synergy, I think something like being able to tap a chunk of spiritweb for the associated ability makes sense. Compounding already covers a fair bit of this, but the stable storage medium of metalminds makes a Compounder not really incentivized to tap as aggressively as this, not to mention that diminishing returns combined with the limits of a given compounders allomantic strength (unless you do further jailbreaking on your magic system) means that even if you're compounding as fast as you can there's a limit on how much you can realistically tap in a given amount of time. By contrast, tapping a spike almost demands that you tap it as quickly as possible if it isn't already spiked into you, and it seems like you can withdraw that chunk of spiritweb very quickly to me. We obviously don't have a term for the 'size' of any of these pieces of investiture, because prior to this nobody really cared about how much space Feruchemical charge relative to Hemalurgic charge, but if Feruchemy's diminishing returns are based on the amount of charge being withdrawn at a time, it's possible that withdrawing X amount of the fundamental soulstuff that provides strength might not hit diminishing returns, even though it'd provide as much energy as drawing out a whole lot of strength. I'm not sure I'm explaining this part clearly. Like, let's say Feruchemy is a hose, and for some reason the harder you pump this hose the leakier it gets. You could get a whole lot of power in a very short amount of time out of pumping a single drop of rocket fuel without springing any leaks, even though pumping the equivalent amount of power in gasoline would make the hose leak a whole lot. Non-Metagamey: The magic systems have kinda fundamental elements to what they do. Hemalurgy takes power and puts it in a more useful, but less stable, format, namely metal. Feruchemy stores power for later and allows you to withdraw power from metal. The thing getting in the way of Feru/Hema synergy right now is all that pesky Identity putting locks on who can access what. Putting a spike into yourself gives you enough Identity to access your donor's metalminds, but I'm not sure that a muddy jumble of your Identity and a diluted, accidental slice of donor Identity is enough to access something as fundamental as a piece of soul. Compounding allows Allomancy to access stuff other than the form the Allomancer's powers ordinarily come in, so I think it stands to reason that the right actions allow a Feruchemist to access power from Hemalurgy even though they wouldn't ordinarily be able to access that power.

So, there have been a fair few theories posted about interactions between the metallic arts. Here's what I've got. Unknown Hemalurgic Properties of Metals One of the largest issues with talking about the Metallic Arts is that the properties of the Table of Hemalurgic metals are incomplete. We can infer from the partially complete Hemalurgic Table that 8/16 of the metals steal Allomantic or Feruchemical traits, one each for physical, mental, temporal, and enhancement. From there, though, we have some weirdness we have to deal with. Iron steals physical strength, so from there we might guess that the remaining metals each steal a property that Feruchemy can store, but there are only 8 metals left and Feruchemy has 16 traits it can store among the non-God metals. That said, the knowledge we have about Hemalurgic properties comes mostly from the table at the end of HoA, and it's quite possible it isn't fully complete or accurate. The fact that the Hemalurgic property of Tin is stealing senses rules out the "one metal for each quadrant" theory, not to mention the fact that you would end up with 4 random leftover metals. In order to puzzle this out, we should take a hard look at what the remaining metals we know about steal. Iron: Steals human strength Tin: Steals human senses Zinc: Steals human emotional stability and fortitude. Copper: Steals human intelligence and memories. Iron obviously steals what pewter stores, tin obviously steals what tin stores, and copper obviously steals what copper stores (although it also steals intelligence, which I'll discuss later), but what about Zinc? "Emotional stability and fortitude" reminds me a lot of the way the Coppermind describes tapping an Aluminummind. One thing I will concede though is that 'emotional stability and fortitude' also plausibly sounds like tapping determination from an electrummind. It actually doesn't matter which of those two it is for this theory. Returning to copper for a second, there's a bit of difficulty with 'intelligence' here. Intelligence is a super vague term, and both mental speed and memories only make up a portion of what intelligence is. Nothing besides Zinc and Copper seem like a good fit for intelligence though, so let's just agree that whatever aspect is being stolen here is likely covered by one of those two. Okay, so from the known metals, what do we have? Iron: Steals what pewter(Internal/Pushing/Physical) stores. Tin: Steals what tin(Internal/Pulling/Physical) stores. Zinc: Steals what copper(Internal/Pulling/Mental) stores, possibly in addition to Zinc(External/Pulling/Mental) Copper: Either steals what aluminum(Internal/Pulling/Enhancement) or electrum(Internal/Pushing/Temporal) stores. Noticing a pattern here? All of the metals we know, with the exception of the partial-fit of Zinc, correspond to an internal Allomantic metal. It's entirely possible that the people of Scadrial after WoA and/or the Lord Ruler just straight up don't know the bind points that correspond to the human traits stored by the external metals. If that were the case, then the 8 metals that don't steal Allomantic or Feruchemical abilities would each steal two traits that are Feruchemically storable, one internal and one external. Iron: Steals strength or speed. Tin: Steals senses or weight. Zinc: Steals memories or mental speed. Copper: Steals either (identity or fortune) or (determination or energy) ???: Steals whichever one of those two copper doesn't steal. ???: Steals wakefulness or warmth. ???: Steals connection or investiture. ???: Steals health or breath Each ??? metal here is one of cadmium, bendalloy, electrum, chromium, and necrosil. Whichever one of those isn't used up is the metal that steals Temporal Allomancy. Feruchemically Tapping Spikes So we've all hypothesized about what happens when a Feruchemist taps an unkeyed Hemalurgic Spike. So, we know that a spike pierces the spiritual realm and takes a chunk of spiritweb and the corresponding sDNA with it. I'm strong in the Cosmere not just because I have physical muscles, but because some piece of my sDNA says 'strong', and damaging that part will make me weaker, where adding more of that part will make me stronger. By contrast, Feruchemy works by changing what that sDNA is influencing at any one time. If my spiritweb is ordinarily exerting some constant force on my body telling me to be strong, then when I store in a metalmind I'm redirecting that part of my spiritweb to instead invest in a metalmind. When I tap that metalmind, I have both that metalmind and my spiritweb telling my body to be strong at the same time. Notably though, I can wring more out of my metalminds than just the constant rate of strength my sDNA puts out, at the expense of diminishing returns. Because I have some sort of control over the metalmind that's I don't have over my spiritweb, I can use it in that way. It's probably a good thing that I can't make my spirit put out more strength, because it'd probably do some pretty bad stuff to my spiritweb. But what happens when I have a piece of spiritweb that's in a format that my Feruchemical abilities are more capable of messing around with, and one where I don't have to be afraid of messing up my spirit real bad if I do too much? A chunk of strength I can tap is more than just a lifetime's worth of strength, it's literally the fundamental machinery that translates strength into the Physical Realm. Sure, it's stored in a format that decays very quickly, and it's probably not very efficient to wring every last ounce of strength out of a chunk of soul all at once, but that's still a lot of strength. So, my theory is that an unkeyed Spike is basically a big, rapidly decaying chunk of whatever trait it's taking, and that a Feruchemist can tap it to use the entirety of it all at once. They could tap mental speed to think decades in the span of seconds, or tap sight to act as a human telescope for a few minutes, or tap connection to become one with a culture for a short span of time. Alternately, they could spike themselves with the spike, and have it in a format where it would decay less quickly. If a Zinc Feruchemist was spiked with a zinc spike that stole mental speed, they might for example have a default mental speed of 1.5x, and be able to tap their spike in order to temporarily go higher than that, at the expense of gradually depleting that spike. Worryingly, it's quite possible that depleting the spike would have bad consequences, a lot of spikes only don't kill you because Hemalurgy is magic, so if they suddenly stop being one it's bad. Alternately, the hole in your spiritweb with a big metal spike through it might accidentally make you tap your own spiritweb if your spike runs out. Either way, bad news bears. Compounding Investiture One thing we know from BoM is that a Necrosil Ferring can store Feruchemical and Allomantic ability in the form of Investiture. Given that, we actually have a very sweet form of compounding. Let's assume that we have a Necrosil Twinborn spiked with some other Feruchemical or Allomantic ability, let's say Allomantic Pewter. That Twinborn can store Allomantic Pewter power in their Necrosilmind, and then compound that power. That means that they could use compounding to become orders of magnitude more powerful than an ordinary Pewterarm. What would that even look like, if they could burn pewter so rapidly that their ordinary burn was stronger than another Pewterarm's flare? If they did that for long enough, would they end up being so warped by Pewter that they were to a Savant what a Savant is to an ordinary person? How would that work for a Tineyes or a Seeker? Moreover, how would that work for a different form of Feruchemical ability? What does it even mean to be twice the Brute that another person is? Do you store/withdraw traits more efficiently? Does being more of a Feruchemist even matter?