Trusk'our

My own thought process right now is that crystal Hemalurgy isn't a formal MoI like the Metallic Arts or Surgebinding are, but more a natural circumstance of Investiture. For example, enough Investiture dumped into any object and given enough time will eventually Awaken it as a natural consequence of how Investiture works. I think this crystal spike usage is the same, where a Spiritweb plugged into the body of a host in the right places (perhaps in this case using Spren captured in gemstones, as gemstones are a focus for certain Rosharan Investitures) will cause changes even without a MoI tied to a Shard. If you're interested, I explored this concept a bit further in another thread.

Yeah, that sounds plausible. I mean, in YatNP we have an example of remotely controlling another body while your own is comatose in a safe location, one of which is a body of pure Investiture. Second, you might not even need a true body. Hoid attached a Lightweaving to Design with what appears to be a bit of substantiation, which effectively gave her a physical body to use (though apparently there are some differences, according to Hoid). Going one step further and controlling it remotely shouldn't be out of the question. As to actually making a CS artificially, if you have a Shardpool to dip in like Kelsier, it should be enough to become a Shadow if you die in it.

It depends on how durable their Spiritwebs are and what's taken, I believe. If you pull off a regular attribute or a little raw Investiture they might pull through and could plausibly be repaired via the application of Stormlight like Spren or Plate after they've been damaged. You rip off the Connection that sustains them and I think they'd just die, maybe slowly decay into a regular soul that eventually passes into the Beyond similar to Jezrien (though a small piece still existed in his gemstone prison even then, though it might not have been enough to consider him anymore. Maybe like how a Hemalurgic spike contains a fragment from a soul?) Here's a couple WoBs on the matter.

This is true. Or at least, Metalborn Lifeless cannot continue using their old Invested powers, which should work the same for Fused Lifeless. Still, if you could retain the skill of a Fused you could still get a lot of bang for your buck, I think. Honor's forces struggled facing the Fused before they had Surges, if memory serves correctly, so getting a few super competent soldiers would be great nonetheless.

The Arcanum.

Shardbuddies, I'm really, really excited. I saw this WoB only minutes ago on Brandon's Ghostbloods update: This is something I've been hoping for a long time and didn't think we'd actually get. But it looks like it is coming, maybe even a while before Ghostbloods is released.

Is it one of these?

Technically, there is an added measure of strength when tapping F-iron, but it is not quite equal to their added mass. For example, Wax is able to be lighter on his feet and climb more easily when storing a bit of weight despite it also weakening one's strength a little. Though, I would not be surprised that Unsealed Metalminds do not adapt the Spiritweb to the user's Feruchemy, as it may not be considered a part of them (which would be an excellent way to balance Unsealed Metalminds and make Hemalurgic spikes and natural Metalborn powers more appealing). Perhaps this would be similar to how Honorblades don't bond as deeply as Radiant bonds, which might affect more than just healing.

As a heads up, a very similar question has been RAFOd already, so prepare for such a rebuttal.

It seems that it would auto-repair if given Investiture, similar to Shardplate. Most likely Ishar would have done this and reconstituted the chip into the Blade.

Controlling an individual pierced by too much Hemalurgy is weird. It isn't like puppeteering their body, it's more like an extreme emotional pressure that tricks the mind into thinking and feeling exactly the way the external influence wants. Marsh had most of his own thoughts overwritten by Ruin during HoA, and it took great effort just to maintain a tiny fraction of his former personality. So, let's say your buddy gets a permanent injury, or perhaps was born with a disability that cannot be healed even if you graft on a Bloodmaker's power. You use Hemalurgy to grant them the healing power anyway, then add on three or more little spikes you can easily and safely remove later. Then you give yourself Emotional Allomancy and duralumin Allomancy with Hemalurgy or get an Emotional Allomancer plus a Nicroburst to blast your friend. The Allomancy is meant to change their thoughts so that they are temporarily tricked into believing they aren't in their natural state, allowing them to tap health and remove whatever lasting disability they have as they accept the changes wrought by the intrusive thoughts. It would be a brutal way of fixing the problem and requires access to various Invested powers but might have a shot of working (assuming you can't just do Coppermind/Goldmind shenanigans instead). I did consider that you might be able to use this more aggressively on enemy Invested, Coinshotting low-charge Hemalurgic bits into enemies, then blasting with duralumin/zinc/brass to briefly overwrite a regenerating opponent's physical abilities, but it's probably too convoluted to be useful in an actual fight (given that aluminum will kill Invested more easily, that Hemalurgy/Duralumin + Emotional Allomancy is a big slammer anyway, and that Hemalurgic projectiles will mess your enemies up horribly regardless).

On one hand, raw Investiture will become easier to shape once you have it in you. This still requires a type of instruction to give the power, which Intent might be enough to accomplish on its own, but it sounds like you'd need a power to shape it normally. So, if an Electrum Misting had burned an Atium/Electrum alloy before, maybe they could replicate it with Intent alone, but I believe it would only be their standard power most if not all the time without some extraordinary circumstances. Maybe an Atium Savant could use raw Investiture that way due to the saturation their Spiritweb has.

Marsh and Sazed are still alive too, and some on the Shard are crossing their fingers for Spook's return.

Over on the Cosmere discussion forum I posted my own hypothesis for Kelsier's limits on his powers. In short, I think his limitations are because he is so saturated with Preservation's essence (being a Sliver, Mistborn, and CS) that Ruin's new subservience to Preservation in Harmony also weakens Hemalurgy's effects on Kelsier. He can get little effects, like using a spike as a bridge to the PR, Connecting him to his old bones, but little else.

Don't forget him being a Dawnsliver/periodic Dawnshard. Hoid is a weird case, but it is worth noting that there are ways to bypass the standard limitations on how much Investiture you can get. Ascension is one way, but perhaps a Dawnshard expanding your Spiritweb is another.

Have you read TLM?

I don't know if we have enough evidence to discount it outright. True, purified Dor is very difficult to get, but a simple Lashing to fly might be cheap compared to Twinsoul's or Moonlight's stunts. This would be very hard to do, most likely. Allomantic (and presumably Feruchemical and Hemalurgic) Investiture is in a very ridged system. You could use Breath without much difficulty, however. I think this could be because Awakening and Surgebinding are more "flexible" systems where the practitioner themselves is the shaping force for the Investiture, using Intent (and Commands), while other focuses take priority in systems like Allomancy and Selish arts.

If we're talking about the shape-shifting sapient pseudo-deity kind of dragons, It may be difficult for them to do so. Non-humans like Kandra can bond True Spren, but highly Invested beings such as Returned would pose more difficulty. A dragon is so Invested innately that most magic systems cannot be used by them. So probably not, but less because they're dragons and more because of their high level of natural Investiture. There probably would be workarounds, but they might be too difficult to be worthwhile.

Well, with your mind not being slowed you still have the chance to do mental tasks while you store. Your mind speeds up while you tap, but that's due to your Spiritweb adapting to the influx of Investiture. You could read a book, watch a TV show, do calculations in your head, plan your calendar, or listen to music with little downside I think. You might want to momentarily stop storing to flip a page, jot a note, or change the channel, but that doesn't seem too difficult.

This is a creative use of Steelrunning, but it wouldn't work, unfortunately. Feruchemical steel is a little wonky and only stores your body's own propellent. Possibly. There are parallels that can be drawn between the two powers, though given the previous WoB and the free movements of Wax and Wayne in Speed Bubbles (no slow falling) I think there are still distinct differences. Probably, though given just how much cadmium slows a person down and just how painfully difficult it is to fill a Steelmind I don't think this would be terribly powerful. Tapping the Steelmind alone would be stronger for many situations, I think. Ninja'd by like 5 seconds

As far as we know, no human being has ever received a Blessing intended for a Mistwraith, so it's hard to say for certain. Kandra Blessings are distinct from spikes made for Koloss, targeting different parts and different amounts of the Spiritweb. If you tried taking a pair of Koloss spikes and implanting them in a Mistwraith, you wouldn't get a true Kandra with the Blessing of Potency, for example. As @JustQuestin2004 brought up, Bleeder shows that Kandra can potentially use Hemalurgy to wield Allomancy and Feruchemy, but the standard Blessings don't do this as they're centered around human attributes. Interestingly, ReLuur's Blessing might be something of an exception to this general rule, as it seems to be made of pewter, which transfers physical Feruchemy when used Hemalurgically. Perhaps TLR did some tinkering with some of the Blessings to grant powers to Kandra but given how hard he worked to remove Feruchemy in the Terris and how surprised Harmony was that she could do this it might have just been a fluke from of Marasi's perspective, or the pewter is capable of taking the "sapience" component necessary to enlighten a Mistraith without an attribute boost like most Blessings.

As far as we can tell right now, any Allomancer- even one without Feruchemy- could Compound an Unkeyed Metalmind (though you can't store the extra attribute without Feruchemy. You'd essentially get a boost to the Feruchemical attribute while burning the Metalmind, but with a limited range of effect). No, it won't. It's an excellent idea, but apparently the Hemalurgist's own Identity muddies the original. This can also prevent two Hemalurgists sharing power from a single Feruchemist from sharing their own Metalminds with each other, but the principle is similar to that of Compounding- the original Feruchemist's Identity doesn't match the Allomantic component they have, which is likely what prevents Compounding via Hemalurgy (currently).

This was the prevailing thought process pre TLM, but Marsh comments on how Identity contamination prevents modern Hemalurgy from allowing the creation of Compounders. How Marsh bypasses this limitation is currently unknown. It sort of depends on the type of spike used. Attribute spikes- things like human strength- provide a permanent stream of effect, no additional metals required. Kandra Blessings like TenSoon's stolen iron spikes are a good example of this. Allomantic and Feruchemical powers granted via Hemalurgy function nearly the same, requiring the storing of attributes or the ingestion and burning of metals.

Zinc Feruchemy has to be one of my favorite powers. I also thought that it would be impossible to get a true idea for how it would feel to be one, but I think I have a slight idea for it now. In one of my online college classes an instructor recommended that we increase the speed on videos if we were able to keep up with what was said, which saves tons of time. So recently I was watching a fairly basic video and had it on at 1.75x speed and could still grasp the meaning of everything (though it wasn't particularly complicated and was fairly intuitive). I tried upping it to double speed, but that was a tad too much. Another video I could only go up to 1.5x speed, as the people were speaking slightly faster and the topic was more nuanced. If I understand the math right, a Sparker with my own mental ability could then reasonably store between 25% and 50% of their mental speed and still grasp a standard conversation. True, actual physical speeding up or slowing down one's perception is more of steel's thing, but I think this is as close a frame of reference as we can get in real life since you'd need a little longer to parse the meaning of words spoken while storing mental speed anyway. So if a Sparker decided to save a minimum of 25% mental speed when not needing it, which I now think might involve many daily tasks, you could tap much more whenever you were actually pressed. Maybe a skilled Sparker would never willingly be at their base level, always storing or tapping as circumstance warrented, relying on practice to reflexively use their brain power with maximum efficiency. They'd always be either conserving brain power or increasing it beyond their natural capacity basically whenever they felt the need. This is still limited, but I think it could be a legitimate strategy for a Sparker to use their Feruchemy to its fullest, being able to be quick-wited pretty much "always".

It is also possible to use Atium and Lerasium to obtain Feruchemy somehow (probably by alloying them together in some way and burning the result). Given that Kelsier cannot seem to gain powers from Hemalurgy I find this doubtful. I feel like this is the most likely way we'll see a Fullborn next aside from the Bands- he might already be there, even. It's worth noting that there are also ways a Hemalurgist can help shield from being controlled, such as aluminum helmets, Copperclouds of a sufficient strength, and possibly electrum Compounding as a last-ditch effort. You don't have to worry about hiding spoilers for Mistborn books in this forum, as that's what it's designed for.