Theory: The Maskless are masters of Hemalurgy

[JustQuestin2004 he/him]

So something that was learned about Southern Scadrial is that there is another continent below it reffered to as the 'Maskless'.

We also know that they are considered dangerous by the Malwish, which makes me think that in Era 3 they'll be antagonists.

But something I'm theorizing is how they are so dangerous to the technologically advanced Malwish, so I'm going to theorize on what they probably don't have and single out the possibilities.

1) They probably don't have high amounts of Metalborn like the North, since the Basin has the Terris and Lerasium in their ancestry, thus have by far the highest amount of Metalborn on Scadrial.

2) They likely don't have access to Malwish tech, since the Malwish have access to Harmony's Perpendicularity, which I am willing to bet money on also being a new Pits of Hathsin, except it produces Ettmetal instead of atium. The Malwish control the source of both Ettmetal and Unsealed Metalminds and considering their rather frigid relations to the North I doubt they'd let their literal enemies have access to any kind of tech.

So if they likely don't have access to lots of Metalborn or Magitech, what could they have access to? Hemalurgy.

Specifically I think they've taken the attribute Hemalurgy (Iron, Tin, Copper, Zinc, Etc) as far as they can go, making Hemalurgic Constructs unseen by the rest of Scadrial. Such as different versions of Koloss but using the other metals instead.

After all if you can make anyone a near-genius with 4 Copper Spikes then it should be easier to make greater strides with Hemalurgy than anyone else, and narratively it doesn't make sense that we've seen nearly zero experimentation with the attribute Spikes in the story thus far, only the Koloss and the Kandra.

Though this is just pure speculation and wishful thinking on my part.

Edited February 29 by JustQuestin2004

[Treamayne]

1 hour ago, JustQuestin2004 said:

Though this is just pure speculation and wishful thinking on my part.

If true, the Maskless could also be "dangerous" because they attempt to spike what few Metalborn the SoScads do have. . . 

[Returned]

I like the idea a lot! Let's flesh it out a bit more.

1. Knowledge of Hemalurgy would be a unique advantage, but I would be curious as to how they gained that knowledge. Even the Lord Ruler struggled to make more than his three types of construct, and he personally Ascended, lived for a thousand years, and had access to compounded F-zinc as well as F-copper. The Set has done some amazingly fast work learning about Hemalurgy in a short period of time, but hasn't made any new constructs. I think that the best avenue for this is to think about Bleeder, who produced the only new constructs we see in-text. Could a Shard other than Harmony or Ruin have that kind of expertise, and be active on Scadrial alongside Autonomy?

2. How and when might they have split from the rest of the Southerners, and how much "Metallic Arts essence" could they have taken with them? It seems like in the early days the Malwish just barely survived the Ice Death, but we don't really know how many Excisors they have nor how they work. Could there have been enough to support a second population? How many Metalborn were there, and how many could the Maskless (or their forebears) have taken away from the rest without dooming them?

3. How dangerous are they, really? It seems hard to think that they would be a major threat to the Malwish, who are so organized and technologically capable, especially since their society seems relatively stable (and certainly not yet conquered or known to be engaged in a consuming war, the latter of which seems unlikely if they were preparing for war with the Northerners). I wonder if the Maskless are just strong enough to not really be conquerable by the Malwish, and their Maskless-ness is more culturally dangerous to the Malwish. Rejecting masks altogether seems like it would be pretty subversive.

4. If they do not have many Metalborn, and never did, then how much Hemalurgy could they have engaged in, and how well could their reserves of Metallic Arts power survive centuries of Hemalurgic degradation? What features could new types of construct have that would be worth the cost?

5. There were eleven Lerasium beads at the Well (nine for Rashek's favored friends, one for Hoid, and one for Elend). But Preservation's numerical jam is 16. So were there five more? If so, what happened to them? If the Maskless had a lot of Metalborn the Malwish would probably know and not be able to deal with them well in a conflict, at least in the early days before their technological developments took off. So perhaps the Maskless are dangerous but not hostile to the Malwish? Or maybe they've used the Lerasium in a different way than eating it and gaining Mistborn, as Sanderson has stated is possible with the right knowledge... tantalizing, but I don't know how to even guess at what those different ways might be.

[Trusk'our he/him]

4 hours ago, JustQuestin2004 said:

So something that was learned about Southern Scadrial is that there is another continent below it reffered to as the 'Maskless'.

We also know that they are considered dangerous by the Malwish, which makes me think that in Era 3 they'll be antagonists.

But something I'm theorizing is how they are so dangerous to the technologically advanced Malwish, so I'm going to theorize on what they probably don't have and single out the possibilities.

1) They probably don't have high amounts of Metalborn like the North, since the Basin has the Terris and Lerasium in their ancestry, thus have by far the highest amount of Metalborn on Scadrial.

2) They likely don't have access to Malwish tech, since the Malwish have access to Harmony's Perpendicularity, which I am willing to bet money on also being a new Pits of Hathsin, except it produces Ettmetal instead of atium. The Malwish control the source of both Ettmetal and Unsealed Metalminds and considering their rather frigid relations to the North I doubt they'd let their literal enemies have access to any kind of tech.

So if they likely don't have access to lots of Metalborn or Magitech, what could they have access to? Hemalurgy.

Specifically I think they've taken the attribute Hemalurgy (Iron, Tin, Copper, Zinc, Etc) as far as they can go, making Hemalurgic Constructs unseen by the rest of Scadrial. Such as different versions of Koloss but using the other metals instead.

After all if you can make anyone a near-genius with 4 Copper Spikes then it should be easier to make greater strides with Hemalurgy than anyone else, and narratively it doesn't make sense that we've seen nearly zero experimentation with the attribute Spikes in the story thus far, only the Koloss and the Kandra.

Though this is just pure speculation and wishful thinking on my part.

You should have seen my face when I saw the name of this thread 

Overall, I think that this is a really, really cool idea and I hope it's true.

However, while this is a possibility, I don't see a lot of definitive proof for it. Plus, even though a Hemalurgic construct made with copper spikes would probably have some genius-level intelligence, making them in the first place seems unlikely without some Metallic Art hack or Shardic intervention; as @Returned said, Rashek had one thousand years to create new Hemalurgic constructs, yet he never once succeeded, and he already had some personal experience with Shardic manipulation from wielding the power of the Well of Ascension.

[JustQuestin2004 he/him]

7 hours ago, Trusk'our said:

You should have seen my face when I saw the name of this thread 

Overall, I think that this is a really, really cool idea and I hope it's true.

However, while this is a possibility, I don't see a lot of definitive proof for it. Plus, even though a Hemalurgic construct made with copper spikes would probably have some genius-level intelligence, making them in the first place seems unlikely without some Metallic Art hack or Shardic intervention; as @Returned said, Rashek had one thousand years to create new Hemalurgic constructs, yet he never once succeeded, and he already had some personal experience with Shardic manipulation from wielding the power of the Well of Ascension.

Yeah I will admit some bias on my part, though a potential explanation is that Ruin might have whispered the use of Hemalurgy into the minds of the broken, guided them together to form cults and drip fed them lots of Hemalurgic knowledge for the price of human sacrifice.

After all Rashek didn't go over there to rule over things, so they spent the entirety of the Final Empires reign completely untouched by anything else, including Worldhoppers since there was no Perpendicularity there. So nothing would have stopped Ruin from messing with things over there. Though why would he bother when the more important stuff is in the North? Because he'd get bored over waiting for a thousand years without causing death of some kind.

[Rorzikel]

On 2/29/2024 at 11:32 AM, Trusk'our said:

However, while this is a possibility, I don't see a lot of definitive proof for it. Plus, even though a Hemalurgic construct made with copper spikes would probably have some genius-level intelligence, making them in the first place seems unlikely without some Metallic Art hack or Shardic intervention; as @Returned said, Rashek had one thousand years to create new Hemalurgic constructs, yet he never once succeeded, and he already had some personal experience with Shardic manipulation from wielding the power of the Well of Ascension.

It's possible that he didn't try that hard with copper spikes out of fear. Maybe he tried a few times, failed, and then thought it would be better to stick with dumb muscle like the koloss rather than spend his research efforts making servants that were smarter than him.

[Trusk'our he/him]

24 minutes ago, Rorzikel said:

It's possible that he didn't try that hard with copper spikes out of fear. Maybe he tried a few times, failed, and then thought it would be better to stick with dumb muscle like the koloss rather than spend his research efforts making servants that were smarter than him.

Technically possible, yes, but then why wouldn't he have another construct type or two made for dumb muscle tasks?

[Rorzikel]

13 minutes ago, Trusk'our said:

Technically possible, yes, but then why wouldn't he have another construct type or two made for dumb muscle tasks?

I'm not sure I'm following your point. I'm not suggesting infinite placements of koloss spikes for variable possibilities, I'm saying that I believe that there's probably 4-spike construct equivalents to the koloss for the other three human-attribute stealers. And that maybe Rashek never found more options because it was both really difficult and some of the options could be threatening to his rule. The man was basically a Terris supremacist and when faced with risks to his power immediately decided to neuter and enslave his people despite those beliefs, so I can believe he could see the threat and decide to pursue other avenues.

[JustQuestin2004 he/him]

7 hours ago, Rorzikel said:

I'm not sure I'm following your point. I'm not suggesting infinite placements of koloss spikes for variable possibilities, I'm saying that I believe that there's probably 4-spike construct equivalents to the koloss for the other three human-attribute stealers. And that maybe Rashek never found more options because it was both really difficult and some of the options could be threatening to his rule. The man was basically a Terris supremacist and when faced with risks to his power immediately decided to neuter and enslave his people despite those beliefs, so I can believe he could see the threat and decide to pursue other avenues.

Maybe Ruin tampered with Rashek's opinions a bit, since H-Copper and H-Zinc provide Mental and Emotional Fortitude respectively, which would mean anyone using those spikes would become harder to control and influence, which Ruin wouldn't want.

Could you imagine if all the Kandra had Zinc Blessings? That would probably not save them from Ruin's control forever, but it would probably be supremely annoying for Ruin to have to devote more attention just to control them.

Edited March 24 by JustQuestin2004

[Trusk'our he/him]

9 hours ago, Rorzikel said:

I'm not sure I'm following your point. I'm not suggesting infinite placements of koloss spikes for variable possibilities, I'm saying that I believe that there's probably 4-spike construct equivalents to the koloss for the other three human-attribute stealers. And that maybe Rashek never found more options because it was both really difficult and some of the options could be threatening to his rule. The man was basically a Terris supremacist and when faced with risks to his power immediately decided to neuter and enslave his people despite those beliefs, so I can believe he could see the threat and decide to pursue other avenues.

Ah, my apologies. I had assumed you meant that he was attempting to only make more types of constructs from H-iron, as those would be easier to control.

I was thinking along the lines of if he had devoted that time and effort toward that he should have discovered at least a few more if it was realistically possible.

However, I suppose it's possible he didn't try very hard (he was busy with ruling, and then a great sense of apathy later on), so using servants to experiment instead of personally utilizing Fullborn SR hacks to learn new constructs wouldn't be super effective. 

7 hours ago, JustQuestin2004 said:

Maybe Ruin tampered with Rashek's opinions a bit, since H-Copper and H-Zinc provide Mental and Emotional Fortitude respectively, which would mean anyone using those spikes would become harder to control and influence, which Ruin wouldn't want.

Could you imagine if all the Kandra had Zinc Blessings? That would probably not save them from Ruin's control forever, but it would probably be supremely annoying for Ruin to have to devote more attention just to control them.

Also a reasonable possibility. We do know he was messing with Rashek's head, after all, which is why he kept Alendi's journal;

Spoiler

https://wob.coppermind.net/events/200-tweettheauthor-2009/#e4416

Anusien

Why did Lord Ruler not destroy the logbook knowing what trouble Ruin could cause with it?

Brandon Sanderson

A few reasons. First, Ruin had his fingers in the LR’s soul by then already. Subtle things are easier to influence.

He played off the LR’s natural nostalgia and desire to hold onto something so important to his past.

 

[+hwiles]

Honestly, I question and doubt whether we shall ever see true attribute hemalurgy on screen except in the form of random mysterious monsters produced in small volumes just because of how violent, dangerous, and powerful it could be if utilized to its maximum extent possible. Imagine if a society invaded, conquered, and spiked a neighboring country. They could walk away with hundreds of thousands of new super geniuses and superheroes after a relatively brief conflict if they knew what they were doing based on what little has been revealed of the system's governing constraints.

Era 4 scadrians camping over a primitive society could abduct and harvest souls at will to turn themselves into gods...if the cosmere gets that dark it might start to bleed its existing fanbase. Just an opinion; if you're right I suspect that group and its practices will simply have to be contained to prevent cosmere-wide war. Or maybe that's exactly what they'll spark...

[Isilel]

Personally, I think it very likely that the Malwish practice hemalurgy on the terminally I'll and dying as outlined in Spook's little book. Metallic Arts are too  important for their survival and functioning of their society to trust to random chance that they'd have a steady  supply of essential Arts in every generation. 

They really should also have breeding programs and caste restrictions for Metalborn as well, though I doubt that Sanderson will go there, no matter how much sense makes.

[Dofurion]

1 hour ago, Isilel said:

Personally, I think it very likely that the Malwish practice hemalurgy on the terminally I'll and dying as outlined in Spook's little book. Metallic Arts are too  important for their survival and functioning of their society to trust to random chance that they'd have a steady  supply of essential Arts in every generation. 

They really should also have breeding programs and caste restrictions for Metalborn as well, though I doubt that Sanderson will go there, no matter how much sense makes.

Well this is similar to another world we saw recently.

[Treamayne]

2 hours ago, Isilel said:

Personally, I think it very likely that the Malwish practice hemalurgy on the terminally I'll and dying as outlined in Spook's little book. Metallic Arts are too  important for their survival and functioning of their society to trust to random chance that they'd have a steady  supply of essential Arts in every generation.

I'll just point out that the primary piece of medallion tech we still have no information on is "Excisor" which certainly sounds like using Hemalurgy to remove an ability (but unlikely to be giving that ability to a person) - possibly making a Hemalurgically charged "device" which is then used, somehow, in the creation of medallions.  

[Returned]

2 hours ago, Isilel said:

Personally, I think it very likely that the Malwish practice hemalurgy on the terminally I'll and dying as outlined in Spook's little book. Metallic Arts are too  important for their survival and functioning of their society to trust to random chance that they'd have a steady  supply of essential Arts in every generation. 

They really should also have breeding programs and caste restrictions for Metalborn as well, though I doubt that Sanderson will go there, no matter how much sense makes.

Interesting angle, as Kelsier was involved in the development of Spook's book, was the Sovereign to the Malwish, and was already dependent on Hemalurgy when he visited the South.

I wonder how much the Malwish need Metalborn powers outside of what the medallions grant at this point in the story. It seems like once you have a handful of the key unsealed metalminds you'd be able to keep producing them without necessarily having fresh Ferrings or Mistings born every few years or needing more Hemalurgic spikes than they already have, even if having Metalborn or Hemalurgists makes the process easier or better in some way. We know so little about how those metalminds are produced I wouldn't feel like betting too much on it, but the fact is that there seems to be a pretty sizeable population in the South that depends on those medallions and so it seems unlikely that they are teetering at the edge of disaster in terms of access to them. Maybe they've been limiting their population growth to what their medallion supply can support?

As to the breeding programs and caste restrictions, Sanderson already did that and it was not really effective so I'm not sure I'd sign on to such things making inescapable sense. The time period of the first three Mistborn books had caste restrictions (routinely violated) and at least ad hoc breeding programs related to keeping Allomancy in family lines. It worked to slow the dissipation of Allomancy somewhat but that appears to be as good as it got.

The breeding program for the Terris (as the Keepers approached it) may have worked in the manner you're describing though, so maybe there is some hope for it (if their initial stock of Metalborn is adequate). Otherwise the goal of "more and stronger Allomancers/Feruchemists" via selective breeding has been a consistent failure over centuries of in-book time, and coming/already present technological advances seem more promising in that regard while also being much easier and faster to undertake.

Edited March 26 by Returned

[Isilel]

15 hours ago, Treamayne said:

 "Excisor" which certainly sounds like using Hemalurgy to remove an ability (but unlikely to be giving that ability to a person) - possibly making a Hemalurgically charged "device" which is then used, somehow, in the creation of medallions.  

 

Sure, but TLM went out of it's way to point out that no allomantic medallions have been seen by NoScads, yet flying ships machinery needs to be primed by a Coinshot, for example. Also, they have been unable to recharge the medallions that they got in BoM, which suggests that you need something else to recharge their metalminds.

 

15 hours ago, Returned said:

It seems like once you have a handful of the key unsealed metalminds you'd be able to keep producing them without necessarily having fresh Ferrings or Mistings born every few years or needing more Hemalurgic spikes than they already have,

 

I saw no evidence that one can produce or re-charge medallions using other medallions so far, in fact NoScads failure to re-charge the handful they got suggests the opposite. There is also a WoB that medallions are more limited than natural or hemalurgic abilities and in fact we have only seen them working in one direction. I.e. either tapping or storing, but not both for the same ability. The Bands are the only unsealed metalmind that likely could do what you describe, if they allow compounding, but SoScads didn't have them after Kelsier left.

 

15 hours ago, Returned said:

Otherwise the goal of "more and stronger Allomancers/Feruchemists" via selective breeding has been a consistent failure over centuries of in-book time, and coming/already present technological advances seem more promising in that regard while also being much easier and faster to undertake.

 

Stronger perhaps not, though, for instance not allowing allomancers and feruchemists to mix makes full versions appearing  more likely or even possible, but more? Definitely. Or have you forgotten Straff and the fact that the nobles did produce allomancers at a decent clip? Sure, the power levels did get diluted, but they started with just 8 people + the few rare natural mistings, who gradually interbred with a much broader mass of TLR's supporters, who became nobles.

SoScads were starting from the opposite end - just the few natural Metalborn, some of whom became essential for their survival post-Catacendre, while others must have become crucial for further Magi-tech development. And yes, Kelsier as Sovereign with his interest in hemalurgy and probably some imported  Inquisitor spikes, as well as an insight into how Metallic Arts heredity works. 

Edited March 27 by Isilel

[Returned]

On 3/27/2024 at 5:19 AM, Isilel said:

I saw no evidence that one can produce or re-charge medallions using other medallions so far, in fact NoScads failure to re-charge the handful they got suggests the opposite. There is also a WoB that medallions are more limited than natural or hemalurgic abilities and in fact we have only seen them working in one direction. I.e. either tapping or storing, but not both for the same ability. The Bands are the only unsealed metalmind that likely could do what you describe, if they allow compounding, but SoScads didn't have them after Kelsier left.

We don't know enough about them to say much in the general case, and in some practical senses they may well work as you suggest here. If they can't be tapped, for example, then application of the ironminds on Malwish ships becomes very different and are a depletable resource on voyages. But that doesn't mean that the Malwish can't have dedicated Metalborn who deal with the excess weight in some sort of centralized facility. That the Bands could do it all but guarantees that medallions could also do it (theoretically, assuming that the medallions and Bands work according to the same principles), though there are obviously substantial technical hurdles separating the two already.

However, we do have a WoB indicating that medallions grant the ability to store attributes in a metalmind other than the relevant portion of the medallion itself. This seems to suggest that a medallion allowing storage of an attribute would allow storage of that attribute in an appropriate metalmind of another medallion:

Spoiler

Genesis

Can someone using a medallion store Feruchemical traits in a separate metalmind (e.g. not the medallion itself)?

Can Inquisitors store Feruchemical traits in separate metalminds (excluding their spikes)?

Brandon Sanderson

Yes and yes.

General Reddit 2018 (Oct. 8, 2018)

We also do see people tapping an attribute and also storing it, so in at least some cases the Feruchemical ability must be bidirectional (storable and tappable, both):

Spoiler

Pagerunner

When you tap the nicrosil portion of a medallion, will it run out over time? Or is it like a coppermind, where something discrete is taken, used, and returned?

Brandon Sanderson

Good question! Like a coppermind.

General Signed Books 2018 (Oct. 15, 2018)

I really wish we knew, specifically, why the heat medallions at the end of BoM couldn't be refilled. It's a puzzle, especially when compared with some of the Set's similar technology. My current suspicion revolves around Identity of the medallion itself, but suspicion is all it's going to be for a while 

 

On 3/27/2024 at 5:19 AM, Isilel said:

Stronger perhaps not, though, for instance not allowing allomancers and feruchemists to mix makes full versions appearing  more likely or even possible, but more? Definitely. Or have you forgotten Straff and the fact that the nobles did produce allomancers at a decent clip? Sure, the power levels did get diluted, but they started with just 8 people + the few rare natural mistings, who gradually interbred with a much broader mass of TLR's supporters, who became nobles.

I did not forget about Straff but I'm not sure this is the argument you are thinking. By "breeding program" I presumed you meant increasing the proportion of Metalborn among the Malwish by selectively combining lines of descent, and that's the part that we haven't seen work despite at least some efforts to do so. I'm not sure what you mean to indicate with a "decent clip" of Allomancer production, given that we don't have much information on how many existed across generations; if the number of Allomancers per X population increased or stayed the same that would be one thing, but if it dipped it would be exactly the opposite. We have zero evidence (that I recall, at least) that two Metalborn are more likely to produce Metalborn children than one Metalborn and one normal parent.

We know (anecdotally and without citation, but at least from a character in-text) that Allomancy fades pretty quickly outside of strictly noble lineages. From what we've seen it appears that Allomancy and Feruchemy become less pronounced in populations over time absent specific events to offset that (the Lerasium beads for Rashek's friends, Sazed making Spook Mistborn, etc.). We don't know anything about the natural Mistings, maybe that's a baseline rate among Scadrians that hasn't been (can't be?) breached. But in any case it's not as easy as "get a Metalborn parent in the mix" when skaa Allomancers' powers dwindle so quickly across generations. Maybe the Malwish are just stuck with the baseline rate of natural Allomancers and can't alter it via matchmaking-- we don't even know if natural Allomancy is heritable. The unifying trait of consistently heritable Allomancy on Scadrial is Rashek's altering of people into nobles and skaa, with only the nobles getting "extra" access to Allomancy.

Given their dependence on medallions to live it's possible, perhaps likely, that the Malwish probably have about as large a population at any given time as they can support. And if their population is limited by the medallions available then arbitrarily expanding the population generation after generation is a pretty difficult strategy to pursue, especially given that even among the much more Metalborn-rich Northerners Allomancy is pretty rare. If an approach that is "more children lead to more of the useful medallions" doesn't pay off pretty quickly you'd have some problems. Though of course it's possible that the limiting factors on Southern populations are not related to the number of medallions available, in which case that pressure would be far less intense. And all of that leaves aside other issues (practical, cultural, or social) which a breeding plan could introduce.

Edited March 28 by Returned

[Dofurion]

This conversation has made me wonder something: What would happen if we had an isolated population of Mistborns reproducing with each other?
Let's say that in era 4 they managed to recreate a couple or two of Mistborns and sent them to a newly terraformed planet to live there without external interference. Would the entire population be Mistborn or would they still decay and be Misting?

[JustQuestin2004 he/him]

On 3/28/2024 at 2:54 AM, Dofurion said:

This conversation has made me wonder something: What would happen if we had an isolated population of Mistborns reproducing with each other?

This is a big part of what allowed Feruchemy to not dilute for so long. The Terris were insular and married within, so the genes of Feruchemy didn't suffer from much dilution.

On 3/28/2024 at 2:54 AM, Dofurion said:

Let's say that in era 4 they managed to recreate a couple or two of Mistborns and sent them to a newly terraformed planet to live there without external interference. Would the entire population be Mistborn or would they still decay and be Misting?

You would need a lot more than a handful of people to start an actual population without resulting in very, very large amounts of inbreeding. But if you could get around that issue, and make sure the population had enough Preservation in their souls to make them all Mistborn, then technically yes. Though I'd imagine you'd still get some Mistings here and there.

Unless the Connection the future generations have to whatever planet they're on starts to degrade the Connection to Preservation, so then no.

[Isilel]

@Returned:

Airship Iron Feruchemy makes it lighter, there is no loss of function if it can only ever store weight. If you want to descend, you just store less or stop entirely. There is no reason to tap weight ever. Filled metalminds just get replaced with new chunks of iron on a regular basis. 

I don't remember any examples of people storing and tapping the same attribute  via medallions. Weight was always ever stored, heat and Connection tapped.

I honestly don't understand how the storing weight part of the handful of medallions that NoScads had, could have been depleted, if F-Nicrosil works more like F-Copper, as per WoB. My impression is that Sanderson just didn't want medallions to be used by Our Heroes in TLM,  saving them for Era 3. Which is why the Ghostbloods, illogically, also didn't have any. It all felt very contrived, IMHO.

Anyway, the way the use of Bands was depicted in BoM paints them as different from the medallions in principle, not just in  scale. For one thing, TLM really stressed that no allomantic medallions have been seen by the Northerners, so they might not exist yet. Even feruchemical applications appear to be limited to a few metals only. IIRC there were also differences in how accessing either felt to the protagonists.

I commented in another topic on the "fading" of Metallic Arts, but we have a WoB that in Era 2 they have become as diluted as they are going to be. I'd also like to point out that Feruchemy hadn't been getting weaker or rarer among the Terris prior to TLR's breeding program and subsequent out-breeding. Which suggests to me that maintaining at least a  constant level of a Metallic Art in an isolated population  does work. 

There is no reason to think that Metallic Art's are not heritable - didn't Kelsier even specifically point out that they are in his conversation with Sazed in the epilogue? And he is a sliver of Preservation and should know.

If Mawlish population growth is limited by their ability to produce medallions and they need Metalborn to do so, this would be a very strong incentive for them to want to encourage said Metalborn to have many children and to mate with each other, keeping Mistings and Ferrings well apart, of course. Metalborn being a miniscule part of their population, this wouldn't  be any kind of risk. Ditto application of Hemalurgy as outlined in Spook's book, to accumulate a pool of Metallic Arts  over generations.