Reverse-compoundability updated for TLM

[Koloss17 She/They]

This shall be the almighty list of reverse compounding for all books thus far. Feel free to add on to anything I missed. 
 

for those of you unaware, reverse-compounding is like a weaker form of full on compounding. Compounding is a magical hack that squeezes an abnormal amount of feruchemy from a metalmind when it is burned. Reverse compounding is a simple breaking of the end-neutrality of feruchemy by using some sort of outside force to increase a storable ability. This basically allows you to do a few cool things, most importantly of which is the ability to become a feruchemical savant. 
 

Reverse compounding is most easily done with a combination of allomancy and feruchemy, so we’ll start there. My list will be going down each feruchemantic ability and seeing what other forms of allomancy/feruchemy can be reverse compounded in the metalmind. This will not be covering how other magic systems affect the mix, which will likely be a separate post.

I will also note that something like storing weight while tapping strength does not count as reverse compounding, as that extra weight still comes from you. While it sure is nice, and enables extra versatility within metalminds, it ain’t reverse compounding.

I also will not be counting compounding for this post, as that’s fairly self-explanatory.

with all that out of the way, let’s get started

Iron: Iron stores weight, but doesn’t do much else. As we have seen in the books, it has been quite versatile, but it doesn’t do much reverse-compounding wise. 
 

Steel: now steel’s more interesting. You can reverse compound pewter’s extra speed, which can end up being quite useful without inhibiting pewter much. You could also maybe reverse compound F-iron, but it seems unlikely. Bendalloy could maybe be used to reverse compound, but it seems extra unlikely, as bendalloy does diddly squat to your body’s capabilities. 

Tin: tin is the king of reverse compounding, easily beating any other metal. With tin you can store any extra senses created by metals, including steel/iron sense, bronze sense, as well as atium, electrum, and gold shadows. Additionally, it can store extra balance gained from A-pewter and F-steel. I would argue it can also store the G-force resistance from F-steel as well. Of course, it can also reverse compound senses gained from A-tin. For those keeping track, that means that F-tin can store every physical allomantic ability, as well as 4 others. That’s 8 of the 17 twinborn combinations that can reverse compound! And that’s not including the feruchemical reverse compounding. The main downside is that each of these effects that are stored are quite important to the functioning of the other ability, so you can’t do much with the other metal while you are reverse compounding it.

Pewter: pewter stores physical muscle mass. Unfortunately, this means it is unable to even reverse compound with A-pewter, which doesn’t affect muscle mass at all. A useful feruchemantic metal, but not for our sake.

Zinc: zinc is actually quite interesting. Atium has shows that it increases mental speed, as does F-steel. You could argue that you could store the additional mental speed from a bronzemind, but sadly that would not count as reverse compounding.

Brass: brass stores warmth. I had thought before TLM that brass did not have anything it could reverse compound, but due to Wax subconsciously burning pewter to stay warm in the water, we know know that A-pewter can be reverse compounded! This is actually really convenient for a twinborn, as the extra warmth granted from pewter is almost never valuable, enabling the user to reverse compound whenever pewter is burned.

Copper: copper stores memories. While useful, it has no reverse compounding applications that I can see.

Bronze: bronze stores wakefulness. Pewter assists with wakefulness, if I recall correctly, so that could likely be reverse compounded. Past that, while there is uses for assisting with F-gold or F-electrum, neither would really count for reverse compounding.

Chromium: Chromium stores fortune, which is a finicky thing in the Cosmere. Atium gives some sort of fortune, yet I have no clue how that would exactly work. Would it spawn atium shadows? Who knows. So there are reverse compounding capabilities, but they are limited and weird.

Nicrosil: Nicrosil stores investiture, specifically innate investiture, which is your ability to use a certain ability. While it is fundamental for the process of making unsealed metalminds, it does not have any reverse compounding uses.

Aluminum: Aluminum stores identity, which is weird, but not helpful here.

Duralumin: Duralumin stores connection, which can be very useful for a worldhopper, it does nothing here.

Cadmium: Cadmium stores breath. F-gold can help squeeze some extra breath out of you when storing, but doesn’t reverse compound. I think it’s fair to say pewter can help here, as pewter allows you to survive with less air. 
 

Bendalloy: Bendalloy stores energy, specifically caloric intake. So while you would think pewter, tin, F-steel, or F-bronze would allow reverse compounding, I don’t think it does. You could maybe do something with F-gold, but it wouldn’t really be reverse compounding. 
 

Gold: gold stores health. I think it’s safe to say that you could reverse compound with pewter. Interestingly enough, I think there’s some interesting shenanigans you can do with F-aluminum and identity, as gold acts based off of your spiritual identity. Wouldn’t help for reverse compounding, but an interesting note.

Electrum: electrum stores determination. You sadly cannot riot yourself to make you more determined, but you could get other people to do that for you, allowing you to reverse compound. Don’t know how useful it would be, but a cool thought.

Atium: atium sort of stores age. While I think there’s some weird applications with temporal allomancy and speed/slowness bubbles, I’m not sure it would actually reverse compound. An interesting question though.

 

Alright, I think that’s all of them. For those keeping track, pewter is the best allomantic metal at reverse compounding, reverse compounding with 7 of the 17 feruchemantic metals. Tin is the undisputed best at reverse compounding on the feruchemantic side, with a whopping 8 out of 17 allomantic metals enabling reverse compounding. 8 of the 17 feruchemantic metals can reverse compounded without actual compounding, and 9 of the 17 allomantic metals can help reverse compound. If you have more reverse compounding instances, please let me know. It’s really cool to see, and I hope we see some interesting applications in-world.

[Friendshipspren he/him]

Strenght gained from A Pewter can be stored in F Pewter. That's how tlr was so strong without being massive muscle wise 

[Koloss17 She/They]

1 hour ago, Friendshipspren said:

Strenght gained from A Pewter can be stored in F Pewter. That's how tlr was so strong without being massive muscle wise 

From my understanding, he gained that through compounding, not reverse compounding. Now technically compounding also reverse compounds, but since every compounded metal does that, I chose not to include it in the list.

[StanLemon]

As someone who read Final Empire again very recently. TLR had his muscles did indeed grow when tapping strength. Specific, after Vin ripped his metalminds away, the narration explicitly described his muscles deflating like Sazed's muscles did. The real question then is, how much of his phenomenal strength that let him elbow Marsh so hard he flew across a room and still hit the wall hard enough to daze Marsh who was presumably was burning Pewter himself came from his powerful Allomancy and how much came from tapping strength? The narration made just described TLR as impressively muscular instead of hulking. 

If F-Pewter can truly store A-Pewter strength, it seems likely that it still stores your muscle mass but because your muscles are stronger from the A-Pewter that it needs to store less muscle per unit of strength 

[Frustration he/him]

On 11/22/2022 at 9:26 AM, Ookla the Headmuncher said:

for those of you unaware, reverse-compounding is like a weaker form of full on compounding. Compounding is a magical hack that squeezes an abnormal amount of feruchemy from a metalmind when it is burned. Reverse compounding is a simple breaking of the end-neutrality of feruchemy by using some sort of outside force to increase a storable ability. This basically allows you to do a few cool things, most importantly of which is the ability to become a feruchemical savant.

Compounding is using allomancy to power feruchemy, generally when people refer to reverse-compounding they talk about powering allomancy with feruchemy.

[Koloss17 She/They]

17 minutes ago, Ookla the Frustrated. said:

Compounding is using allomancy to power feruchemy, generally when people refer to reverse-compounding they talk about powering allomancy with feruchemy.

That’s exactly what I’m talking about. You burn allomancy, which gives you ability that you don’t normally have, like steel sense, and you then store it in a metalmind. I just put in a vague definition to make it apply to non-allomantic sources like (Warbreaker)

Spoiler

Lifesense from breaths stored in a tinmind

 

[lacrossedeamon]

On 11/22/2022 at 11:26 AM, Koloss17 said:

Pewter: pewter stores physical muscle mass. Unfortunately, this means it is unable to even reverse compound with A-pewter, which doesn’t affect muscle mass at all. A useful feruchemantic metal, but not for our sake.

There is a WOB about using A-Pewter to fill F-Pewter. Brandon says it’s possible just that it’s easier to do regular compounding.

On 11/22/2022 at 11:26 AM, Koloss17 said:

Nicrosil: Nicrosil stores investiture, specifically innate investiture, which is your ability to use a certain ability. While it is fundamental for the process of making unsealed metalminds, it does not have any reverse compounding uses.

Do we know that it is only innate Investiture? F-Tin you can decide which sense to store. Can you decide between kinetic and passive Investiture for F-Nicrosil?

On 11/22/2022 at 11:26 AM, Koloss17 said:

Duralumin: Duralumin stores connection, which can be very useful for a worldhopper, it does nothing here.

Since you added Atium don’t forget that A-Lerasium forges Connection (or at least theorized so) which could possibly then be stored by F-Duralumin

On 11/22/2022 at 11:26 AM, Koloss17 said:

Iron: Iron stores weight, but doesn’t do much else. As we have seen in the books, it has been quite versatile, but it doesn’t do much reverse-compounding wise. 

Here is a weird one because you are focusing on storing usually a secondary A-metal attribute into an F-metal but what about a secondary F-metal attribute into a different F-metal (obviously not something a regular Twinborn can do but someone spike might) and so the added weight from F-Pewter could be used to fill F-Iron.

[alder24]

6 hours ago, lacrossedeamon said:

Do we know that it is only innate Investiture? F-Tin you can decide which sense to store. Can you decide between kinetic and passive Investiture for F-Nicrosil?

F-nicrosil stores the ability to use investiture, not investiture itself. I'm not even sure if that's innate investiture, as is being Mistborn giving you additional investiture to your soul? It certainly gives you a connection to Preservation. But you can store Divine Breath (WoB), and that's innate, so it's one example at least. And storing investiture makes you invisible to Lifesense (WoB), like Drab are. And because Drabs have lower innate investiture levels than others, it seems like Nicrosil can store innate investiture which would hide you from Lifesense, so Scadrians should be able to store their fragment of Preservation as well.

We have no WoB about storing kinetic/static investiture, I think. How would you store investiture that is being used? Static is more plausible, but I think abilities and innate are all nicrosil can store.

[lacrossedeamon]

1 hour ago, alder24 said:

We have no WoB about storing kinetic/static investiture, I think. How would you store investiture that is being used? Static is more plausible, but I think abilities and innate are all nicrosil can store.

I would assume that you burn a metal allomantically which acts as the key to the spiritual realm but if you store in F-Nicrosil at the same time instead of an Allomantic effect happening the amount of Investiture that would power that effect instead gets stored.

[cometaryorbit]

I am not sure that storing A-pewter strength in F-pewter, or A-pewter health in F-gold, or A-tin senses in F-tin, is really what people have meant in the past by "reverse compounding".

That term (which I think is a fanon one) seems to mean what TLR did to get the Allomantic strength he displayed (Soothing hundreds of thousands of people) when his "essential Allomantic strength" was the same as Elend's.

The A-tin storing in F-tin or A-pewter storing in F-gold trick just gives you more senses or health, not more Allomantic strength.

Before TLM I couldn't even see what powering Allomancy with Feruchemy could mean, since Allomancy's end-positive and fueled from an unlimited source (Preservation). It didn't seem like adding a new power source would help (it does with Feruchemy since Feruchemy is end-neutral). But we see in TLM that liquid Investiture allows Mistings to use their Allomancy at much greater than usual strength. That kind of surprises me - I'd thought Allomantic strength's upper limit was set by the Allomancer, since Preservation is an unlimited source - but I suppose if the Allomancer's Physical body is taking in liquid Investiture, then their Spiritual ability to draw from Preservation isn't relevant.

So given that Allomantic strength isn't a limit if you have a new power source, "powering Allomancy with Feruchemy" could genuinely be useful since the peak rate of draw is much higher in Feruchemy (it would be kind of like duralumin's Allomantic boost but more controllable).

The problem is that no metalmind seems to store "Allomantic strength" as such. Even nicrosil in medallions stores discrete powers, not a 'pool' of strength. But the Bands do seem to have a pool of strength, since Wax says their Investiture stores are "running low" - so maybe there are two ways to use f-Nicrosil.

The other question is whether there's a way to "hack" the system to store a coppercloud instead of memories in a coppermind, or an Ironpull instead of weight in an ironmind.

[Koloss17 She/They]

You know, I’d love to know if I’ve been calling reverse-compounding the wrong thing this whole time. I was honestly under the impression that it was the breaking of end-neutrality of feruchemy, but honestly I could be totally wrong.

[cometaryorbit]

Well, I think it's a fanon term, and I'm not even sure everyone necessarily has the same thing in mind for what they mean by it. But I think the basis for it is this:

https://wob.coppermind.net/events/246/#e5494

I was for a while very skeptical about this being a real thing/correctly interpreted*. But TLM showing that an alternate power source can boost Allomancy beyond the Allomancer's natural Allomantic strength does make it more plausible. I also found this WoB which at least confirms that something like that exists:

https://wob.coppermind.net/events/2/#e2625

Though the comparison to Southern Scadrian Metallic Arts tech is strange. If it means it uses nicrosil just like medallions... well, ok, but why did TLR have that? TLR shouldn't have had access to nicrosil - he knew about it, but probably TFE tech couldn't make it, and anyway they didn't find any unknown metals on TLR's body.

*because this is a paraphrased WoB, and it says Brandon "implied" it rather than outright stated it - it's also very old so subject to possible mechanics changes in the writing of Era 2. And also because powering an end-positive system drawing on an unlimited source with an end-neutral system didn't seem to make sense/be useful. And also because of the nicrosil issue.

[Tglassy]

Brandon has stated it is possible to store just the strength from A-Pewter in an Pewtermind, thus bypassing the usual muscle growth and just gaining the strength.  Compound that, and you can completely fill a metalmind with oodles and oodles of Strength with no side effects of larger muscles.  

That said, my thought, too, was that Reverse Compounding was using Ferchemy to increase Allomancy.  I suppose that storing Allomantic Strength in a Pewtermind, then tapping that strength, could cound, since you could store an entire nugget of Pewter into a metalmind, then pull it all out at once instead of being limited by your burning speed, but that doesn't seem quite right.  

Personally, I think it has to do with tapping Investiture.  What is that, Nicrosil?  

2 hours ago, cometaryorbit said:

The problem is that no metalmind seems to store "Allomantic strength" as such. Even nicrosil in medallions stores discrete powers, not a 'pool' of strength. But the Bands do seem to have a pool of strength, since Wax says their Investiture stores are "running low" - so maybe there are two ways to use f-Nicrosil.

The medallions aren't just metalminds, they're something else.  If they were just metalminds, then you would acutally be able to use the Medallions to TAKE powers and GIVE them to people.  You'd store your power in the metalmind, then someone else would tap it, taking it out.  Like memories.  Then the second person would just have the power, and not need the metalmind.  

Instead, they give powers when you touch them, like Honorblades.  Which means they are doing something different.

I think that, if it stores the ability to use Investiture rather than just Investiture, then you could use Nicrosilminds to increase Allomancy.  Your powers are weaker while storing, and stronger when tapping.  If that's the case, it would explain TLR's power, because he could just compound his Allomantic Strength to have a near infinite pool of Allomantic Strength to pull on, thus allowing him to soothe the emotions of dang near an entire city even through copper clouds.  

[alder24]

13 hours ago, Tglassy said:

If that's the case, it would explain TLR's power, because he could just compound his Allomantic Strength to have a near infinite pool of Allomantic Strength to pull on, thus allowing him to soothe the emotions of dang near an entire city even through copper clouds.  

I always understood that because Rashek used the power of the Well, he made himself an extremely powerful Mistborn, far above anything Lerasium could give you. It's confirmed by WoB (https://wob.coppermind.net/events/63/#e685). But it doesn't mean that Rashek didn't also use reverse compounding.

13 hours ago, Tglassy said:

I think that, if it stores the ability to use Investiture rather than just Investiture, then you could use Nicrosilminds to increase Allomancy.  Your powers are weaker while storing, and stronger when tapping.

There is WoB that might be about it, or just about how regular compounding works: 

Spoiler

Necarion

The compounding trick that the Lord Ruler performed. When you're storing Investiture, are you storing your "Mistborn-ness" or all the powers individually?

Brandon Sanderson

All of the powers individually.

Necarion

Oh okay!

Brandon Sanderson

Yeah, the compounding trick. Really what's happening is you're fueling Feruchemy with the power of Allomancy, but you're filtering it through you, and then you're storing it.

Necarion

So it's not that you're a more powerful mistborn when you've tapped [investiture]

Brandon Sanderson

No, good question.

Arcanum Unbounded San Francisco signing (Nov. 30, 2016)

 

So there is a way to reverse compound - use Feruchemy to fuel Allomancy, Rashek could use it and thus became even more powerful than he was, but his regular power was still above Elend's as it was granted to him with the use of the Well. To add to it, there is this WoB suggesting that hemalurgy was used to achieve the most dramatic effects:

Spoiler

Darxbane

In an annotation from book one, it is mentioned that The Lord Ruler needed all three magic systems in order to do what he did. I always assumed that it meant his Hemalurgy enhanced his Allomancy. Did Marsh get a double power, or is the Feruchemy-Allomancy combo enough? (a sidebar to this question is whether or not stacking abilities is possible through Hemalurgy)

Brandon Sanderson

He used Hemalurgy to pull off his most dramatic effects. Marsh didn't need them, but it makes things much easier.

Hero of Ages Q&A - Time Waster's Guide (Oct. 15, 2008)

 

[cometaryorbit]

8 hours ago, alder24 said:

I always understood that because Rashek used the power of the Well, he made himself an extremely powerful Mistborn, far above anything Lerasium could give you. It's confirmed by WoB (https://wob.coppermind.net/events/63/#e685). But it doesn't mean that Rashek didn't also use reverse compounding.

There is WoB that might be about it, or just about how regular compounding works: 

  Hide contents

Necarion

The compounding trick that the Lord Ruler performed. When you're storing Investiture, are you storing your "Mistborn-ness" or all the powers individually?

Brandon Sanderson

All of the powers individually.

Necarion

Oh okay!

Brandon Sanderson

Yeah, the compounding trick. Really what's happening is you're fueling Feruchemy with the power of Allomancy, but you're filtering it through you, and then you're storing it.

Necarion

So it's not that you're a more powerful mistborn when you've tapped [investiture]

Brandon Sanderson

No, good question.

Arcanum Unbounded San Francisco signing (Nov. 30, 2016)

 

So there is a way to reverse compound - use Feruchemy to fuel Allomancy, Rashek could use it and thus became even more powerful than he was, but his regular power was still above Elend's as it was granted to him with the use of the Well. To add to it, there is this WoB suggesting that hemalurgy was used to achieve the most dramatic effects:

  Hide contents

Darxbane

In an annotation from book one, it is mentioned that The Lord Ruler needed all three magic systems in order to do what he did. I always assumed that it meant his Hemalurgy enhanced his Allomancy. Did Marsh get a double power, or is the Feruchemy-Allomancy combo enough? (a sidebar to this question is whether or not stacking abilities is possible through Hemalurgy)

Brandon Sanderson

He used Hemalurgy to pull off his most dramatic effects. Marsh didn't need them, but it makes things much easier.

Hero of Ages Q&A - Time Waster's Guide (Oct. 15, 2008)

 

Well, there's a couple of cans of worms here.

1) In the HoA epigraphs, Sazed/Harmony specifically states that TLR's "essential Allomantic strength" is the same as the other Lerasium Mistborn. That WoB doesn't say TLR was stronger, it just says that he got his Allomancy through the Well rather than a bead.

However, its possible that the same strength idea was retconned at the same time as the Well thing was established.

But if the line is unchanged in the leatherbounds, then probably not. Can someone with a leatherbound HoA check?

[Now, TLR would have been effectively stronger than Elend even with the same "essential" or base strength - due to experience/skill and near-savantism in the commonly used metals (and quite possibly actual savantism in brass since he seemed to have it on all the time, likely bronze too...) - even without reverse compounding.]

2) That WoB is very unclear. It's not even totally clear that "he" is TLR not Marsh, though probably. And "his most dramatic effects" - excluding moving the planet and reshaping the world with the Well - were plausibly creating koloss/kandra/Inquisitors and controlling vast numbers of koloss. TLR 'using' Hemalurgy doesn't have to mean TLR himself was spiked, it could mean creating Hemalurgic constructs.

Edited February 17, 2023 by cometaryorbit