Xanpheon

The concept of Spren as a whole is quite interesting. Obviously they're splinters, but to what extent are "splinters" and "spren" interchangeable? WE know that the morphological differences between each "type" of sentient spren is largely down to what proportion of Cultivation and Honor make up each of them, but what about the emotionspren, or other lesser spren? We know they already existed before any of hte Shards arrived on Roshar, they were part of what prompted the creation of the sentient spren by the two Shards. They're obviously Spren too, but are they associated with any shardic intent? Or are they, instead, perhaps proof of splinters existing independent of Shardic Intent? The Wind wanted to protect "all spren" from being absorbed by Odium. This seems to include emotionspren and Cultivationspren, even after the fusion into Retribution he shouldn't have had any control over their constituent investiture as they likely weren't created by Honor.

Not convinced about this, to be honest. Sure, there's an element of that, but the Shardblade can exist without needing investiture to "fuel" it. Deadeye shardblades exist without any stormlight to fuel them - they only "bond" when gems are placed in them, sure, but they can still exist without it. An aluminium gnat would burn out the investiture reserves but I'm not convinced they would stop the shardblade existing in it's already sharp state, even if it loses the soul-burning properties.

While I do understand where you're coming from with this particular stance, I'm not sure I agree. Hemalurgy is ripping away a piece of a spiritweb and stapling it to another entity. Strength, speed, or the spiritual DNA to create a bond to Preservation, allowing the wielder to use an Allomantic power, for example. But using Allomancy as an example for this kind of works against the idea - in the books, advanced Seekers can sense the difference between the "tones" (pulses, but I'm using tones to tie in to the "source" of the investiture) - enough to tell what sort of Allomancy is being used. And Inquisitors don't have a different sensation to their power than anyone else when they use Allomancy - which indicates they still use metal as a key to Preservation's power to allow them to use Allomantic abilities. Similarly, hemalurgy can't strip all identity from investiture as we know that it can allow a spiked Feruchemist to access metalminds made by the person who had their powers stolen from. It tracks the identity of the user - and thus likely also tracks the original "source" of the investiture. I won't argue that it infects their spiritweb with part of Ruin's Investiture and gives whoever the bearer of the shard is a bond to them - we know it does - But I don't think it erases previous shardic affiliations.

Maybe, but unlikely. Shardplate and Shardblade aren't an invested art, they're closer to mechanical uses of investiture - if the wielder is not a Radiant and thus the Shardbearer is just using deadeyes (or unoathed), then the wielder doesn't really use the investiture, per se. Resonances come from the natural interference of two separate Invested Arts/methods of manipulating investiture interacting with each other: Now you might be able to argue that the wielder is "channeling" investiture from the Shardplate, but that isn't the case from the Shardblades. The shardblades don't pass any investiture into the wielder, they fuel themselves with it instead. So even if Shardplates count, there's no countervailing "wave" from the Shardblade to enable the resonance in the first place. In addition to this, though this is less of an issue with the cosmere and more from a plot standpoint, Sanderson has stated that the second half of the cosmere eras are going to be shifting to more and more mechanical uses of investiture rather than being 90% standard invested arts, as they are now. A great example of this is seen in the way spaceships are shown to work, and the Sunlit man - the only "invested art" (and I hesitate to call it even that) on Canticle is the ability to transfer heat. Anything more than that requires manipulation of the Sunhearts to either supercharge a body with investiture, or to fuel various devices. Given that, I don't know if he necessarily wants to run with mechanical uses of investiture generating Resonances.

We know that "raw" investiture - like the Mists - can be repelled under certain circumstances by investiture aligned with other intents. Vin needing to have the Hemalurgically charged earring removed before she could absorb the remnants of Preservations power is the perfect example of this - the Mists no longer enveloped her, the stronger the impact of Ruin became on the world and the stronger Ruin's intent became. It is not exactly a massive leap to extrapolate that if investiture is "charged" with an intent, that it is affected by the user's intent as a result in how easily it can be drawn upon. Another good example of this is Kelsier taking up the power of Preservation using the jar of raw connection, in Secret History. We are shown that while - yes - he could slow down Ruin's destruction of the world in the same way as Vin did, as the connection faded - as the connection was weakened by his intent not aligning with Preservation, so too did his ability to restrain Ruin. Finally, the Shards themselves have some rudimentary consciousness, even those shards that have been held uninterrupted since their formation. While Honor developed more, being "separate" and it's own entity for thousands of years, even with Odium we see that the Shard can be described as having it's own thoughts and ideas, in some way, and fights back or accepts the user. All that to say - yes. I think that for a variety of reasons, the Shards and the Vessels need to be in alignment to bring forth the most power.

So, the issue with this is the only real time we've seen tones used to manipulate investiture is in the Stormlight archive, where it was used to draw investiture from one gem to another - and then to create anti-Investiture, to devastating effect. However, no-one used those same reverberations to draw Stormlight (or Voidlight) from any of the Radiants or Fused in the Final Desolation. They had to use Raysium weapons, which acts as a conductor, and empty gemstones. Considering one of the sides of that conflict is built around the concept of Rhythms and Tones, the Singers, I doubt that if it were possible for them to steal Stormlight just by humming they wouldn't have passed that knowledge to every Singer to give them an edge. And if they can't take Stormlight, one of the more volatile forms of Investiture (in that it dissipates from a living host quite quickly), I doubt they could forcibly steal a Breath.

We know that the size of the Sunheart is somewhat defined by the innate investiture of the person being converted - but that it doesn't necessarily limit the amount of investiture being stored. The traveller from Roshar created a sunheart *notably* smaller than any Threnodite had due to the difference in innate investiture (interestingly, Zellion also commented that the traveller "likely" had breaths, which suggests that Breaths don't count) - and yet Zellion was able to siphon power into the "charged" sunheart to reduce the impact of the torment. I don't think there's any concrete evidence either way, but considering the Sunheart we saw the Scadrians playing with was only identified as having an unusually high amount of investiture in it after it was touched, I doubt that they are expanded by having additional investiture in them.

You do, but I was giving a more "practical" way to achieve a way to see through (in a sense) solid objects.

I think a potential way that this would be achieved more... realistically? Than X-ray vision (which would require a dense source of piercing radiation on the other side of whatever you're trying to see) would be infrared. Humans already have a reasonably accurate sense for temperature based on the skin, and infrared radiation is part of the visible spectrum. You're just using senses the human body has, just magnified and "tuned". Now, is this practical? Unlikely. A tineye would need to be a savant to remotely approach the level of intensifying necessary to be able to pull this off, and that's ignoring the fact that human L-cones tend to peak at around 560nm for the type of light they pick up the best - while infrared tends to hover around 800-900nm. Then again, investiture is a hell of a drug - and I don't think it's beyond the range of possibility that a suitably skilled Tineye could enhance their sight to the point they could see the infrared spectrum and use that as a bootleg "x-ray vision". Though, that does raise another question - we know that you can store different senses in a Tinmind. How far does the subdivision go? Smell and taste are inextricably linked but can be stored separately. Could you store your ability to see specific wavelengths of light? If so it would make this process significantly easier - because I imagine if you've pumped your vision to the extent where you're 50-60% out of your normal visible range of light, everything else might overwhelm the infrared. It's not even necessarily impractical - colours tend to be divided based on the cones, so you could filter based on cones. That would be a weird Malwish medallion to create, but interesting.

How are they not? Look at Ati, for example. Holding onto Ruin for thousands of years changed him irrevocably, turning him from someone that Leras described as the best among them, and incredibly kind, to someone who took great pleasure in causing unimaginable pain and suffering - causing the eruption of a volcano to burn a village alive, among other things, and drove the inquisitors into frenzies of ecstasy when committing murders. The pure concept of Ruin, no matter how Ati justified it to himself by couching in terms of entropy, changed him - warped him. The Shards are masses of investiture imbued with a single pure Intent, and that Intent changes the users (see Tanavast, for example) when the users don't align with the Shard. In a normal being or Adonalsium, those Intents would be restrained and tempered by the existence of all of the other Intents present (if they'd even be present in the same way, as we know the 16 we have aren't the only Intents that were possible to create in the Shattering). But when on their own, there's nothing to hold them back - and thus, they end up warped, driven singlemindedly.

But the question is what does that mean for whatever Adonalsium comes from? It makes sense if they are inherently complete, because they are a balance of all 16 shards and the intents involved. The Shards and their Vessels are unbalanced by not possessing the complete whole of what made up Adonalsium, warping them in an incredibly extreme way - but from everything we know about Adonalsium, they didn't have those issues.

A 4th ideal Kandra is a moderately terrifying concept, but I think what interests me a bit more is how this would interact with Kandra Blessings. Hemalurgy doesn't necessarily repulse other investiture like it does to investiture with Preservation's intent, but would Shardplate be able to replace or replicate the effects of the Blessings by being worn internally?

I think the key thing to remember here is: For a lot of magic systems in the cosmere, "Growth" in power isn't really a thing unless you become a Savant. You have a set level of power available to you, and you just learn how to use it better. Cases in point: Allomancers and Feruchemists are stated to not really improve in power, their capability is "set" from the start. Elend becomes, in terms of raw power, the strongest allomancer of his era (able to control Koloss without Duralumin where Vin needed to use Duralumin) after consuming the bead of Lerasium, while Vin was a much more skilled user of her powers which let her seemingly do more than he could. Spook grew in "power" with his tin after overusing it and becoming a Savant and we see him consuming more tin than others do - significantly more. Accessing more power. Sand Mastery doesn't really have an increase in power under normal circumstances. The number of ribbons one can control never changes unless you Overmaster, and go specifically beyond your limits (and thus pushing yourself closer to Savantism). On Sel, Elantrians are set in the level of power they control, they just get better at drawing Aons. Riina's power comes from being exceptionally good at drawing and "coding" with Aons, not from inherently being stronger than other Elantrians. Nalthis is a little odd, but it's still more or less the same. You can learn to do more with the same amount of power - and you can acquire power from other people to also increase your own capabilities, but each person's individual capability barring breath is dependent on skill, rather than growing power. The Radiant Orders are one of the few ways of organised access to a Manifestation of Investiture that grant a power increase as you improve. Going from barely able to control the investiture to being able to handle larger and larger amounts of power and express it in more and more explosive ways. High Ideal Radiants are probably about as close as we're ever going to get to seeing a Savant in a surge (beyond, specifically, the Soulcasting Savantism we see as a result of overusing Soulcaster fabrials). Their bond either mimics the effect of, or provides a controlled way to advance to a new stage of a state similar to Savantism.

Regarding the second part of your question, though - the best way to detect an Allomancer on Scadrial is still to burn bronze, but any way of sensing kinetic investiture would work (read, any way of sensing investiture that is not in a passive state, like in a Feruchemist's metalminds). There are a couple of ways you could do this - the sand from Taldain is a good example, but Larkins would also probably be able to sense them. The downside being that it would be extremely obvious what you were doing, as Scadrial doesn't exactly have dog-sized insects flapping about the place on the average day. Most of the time you're going to find it easier to just use white sand or, if you're a native Scadrian, just find a local Seeker and pay them (if you weren't a Seeker already).

But what about the anti-stickiness? Those who despise the stick and seek to cast it down?