Compounding Stormlight and Breath

[DarkJester]

Ok. I was just wandering what you guys thought the results of this might be. We are told that twin born's dual powers tend to compound in odd ways, sometimes affecting each other in ways that nether power could produce alone. Wax is a "crashes" I've yet to really see him live up to that title... Basically he could reduce his weight and steel push off of something really hard for an extreme burst of speed. As he is readying to hit his target he could increase his weight many times over, essentially turning himself into a massive boulder flying at the speed of a bullet. That's the idea of compounding, but like a double gold that can increase his healing potential to God like proposition, I'm curious about how other powers might play off each other. We know that Wit is holding breath. Enough to get him to the level of perfect pitch at least. We've also seen that he has used stormlight. Both of which are breathed in, heighten a persons natural abilities, and can be invested into objects. How do you think they would play off each other in someone like Wit who has more than one power.

[Argent he/him]

Woah, slow down there, champ! Let's address things individually

First, I think you are confusing Compounding (the process of fueling Feruchemy with Allomancy, essentially) with Resonances ("side effects" people get when they use multiple sources of investiture, a.k.a. magic). Compounding requires one to be able to use the same metal for both Allomancy and Feruchemy - so neither Wax nor Wayne is a Compounder, because they are Allomantic steel & Feruchemical iron and Allomantic bendalloy & Feruchemical gold Twinborn respectively. This means they both get some weird additional and unique powers that other Mistings and Ferrings, who only have one power, wouldn't be able to reproduce (e.g. Wax can "sculpt bullets away from himself"). Only the "double gold" example from your write-up is considered Compounding.

So let's go Wit now. With everything we've said so far, Compounding Breath or Stormlight (which we haven't seen him use, by the way) doesn't make sense. We've only discussed Compounding in terms of the Scadrian magic systems. Let's take a look at how exactly Compounding works, because it will be useful in a moment:

1. First, a Twinborn (partially) fills a metalmind with whatever trait they want to Compound. Miles Hundredlives, for example, would store health.
2. Second, Allomantically burn that same metalmind you just filled. Recall that Allomancy works by essentially filtering Preservation's power through a specific metal in order to produce a specific effect. What is important here is that the source of the power is external (hence Allomancy being an "end-positive" system). So when you do the same trick with a metal full of Feruchemical charge, Preservation's investiture being "filtered" through it causes the charge to be multiplied - so you end up releasing a lot of health.
3. Which you then store right back in with Feruchemy. 

Why is this useful? Well, first because it makes it clear that you can't multiply Breath or Stormlight with Compounding, because neither is a Feruchemical trait you can store. Except maybe you can! Both Breath and Stormlight are investiture, and there is a Feruchemical metalmind that stores exactly that - it's necrosil.

So, in theory (and Brandon has RAFO'd this very recently), a Necrosil Twinborn who has somehow acquired Breath (or Stormlight) might be able to store that Breath in a necrosilmind, then burn the metalmind Allomantically for a tenfold increase of that Breath. Bam, Compounding!

This makes sense, but is speculative though. 

[Eki]

3 minutes ago, DarkJester said:

As he is readying to hit his target he could increase his weight many times over, essentially turning himself into a massive boulder flying at the speed of a bullet.

Momentum (mass times velocity) seems to be conserved, so he would slow down as he increases his weight.

[Spoolofwhool]

Regarding resonances as Argent mentioned, it is unlikely that Hoid possesses any. Brandon has explained once that resonances only appear when you have at least two powers, but too many, such as being mistborn, results in no resonances because of "cluttering".

[Weltall]

Yeah, he explained it both in real-world terms (he wanted to make Twinborn more special, for example) and in-universe (too many powers override the resonance you might otherwise get) so someone who has multiple magic systems like Hoid probably isn't going to get any such effects. Though having access to multiple magic systems is pretty much a superpower in and of itself.