therunner

That we know of. Pewter cage + large amount of Stormlight would increase the range most likely, possibly larger gem could be required. Neither are bunker complexes, and those are typically smaller/under smaller mountains. And yes, shockwave would propage through corridors, if only there was no way to close the corridors. However, Sibling can open and close the doors/manipulate the structure (seemingly). Point is that Godspren can exert power on the level of modern nukes, hence Sibling could plausibly counteract nuclear explosion. All of Siblings power is concentrated within that mountain as far we know, so this is possibly within scope of their power, as he is hurricane concentrated in single point (power wise). Point is that WW2 nuke simply does not have enough power to melt or shatter stone, not when exploding out in the open. It would have to explode directly next to the mountain, and even then the melt radius would be certainly less then 11 meters (since explosion would have lower pressure areas to expand to), and so would the shatter radius be less then 80 meters. Yes, and as seen above, WW2 nukes simply don't have enough power to melt rock, or shatter it, on the scale of Urithiru (or even on scale of just regular rock formation, when it comes to melting). Destroying it would take multiple nukes at least, even if Sibling had no way to defend itself. And as we already discussed, managing to pull of such attack is going to be very difficult, due to limited attack options. They can rebuild soulcaster fabrial, and make it affect other things. It had model of Urithiru which probably served as 'target'/source of Intent, so you could make similar one that would create 'shield' around the mountain, though it would consumer much more Towerlight to power it. However, it would be within scope of power of awake Sibling. Even if those fabrials cracked under strain (which since they are made directly out of Siblings body I doubt would happen), all they have to do is partially protect inhabitants of the Tower. Combination of closed doors, increased pressure, and lowered temperature would be enough to shield against most of the damage. People standing in the open just ~800 meters away from epicenter, with no shielding, survived in both Hiroshima and Nagasaki. People shielded by a mountain worth of stone and effects of fabrial would survive as well. Sure, there would be losses, but it would not be anything that could not be rectified, and any radiation poisoning would be quickly healed by Edgedancers and Truthwatchers. Hell, there were people who were ~300 meters away from the bomb and they survived! And those had only regular old cinderblock building for protection. Edit: And if ordinary crosswind could carry bomb more than 240 meters away from target, bunch of Windrunner (or one 4th Oath one) could push the bomb completely away from the mountain. As mentioned previously, 4th Oath Windrunner can generate hurricane level air currents, and those would knock the bomb away even if was covered in Aluminum, since air is still air, even if it started moving due to Investiture. Or Sibling could generate such air currents on its own. With luck you could land one nuke, which would damage outer sections on one side of Tower. But there would be no second time.

That is actually a very good point! If single 4th Oath Windrunner can create a column holding back Highstorm, what can fully functional Sibling do? They already have fabrials for pressure control, and you can create soulcasted 'forcefields'. On this note, regular hurricane can produce about as much energy as ~10000 'regular' nukes, some estimates being that hurricane releases same amount of energy as 10 megaton bomb every 20 minutes. Highstorm is larger and stronger than any hurricane on earth and lasts longer. So amount of energy that Godspren can provide is orders of magnitude greater than WW2 nukes. Even re-scaled to account for energy vs work (in that nuke deposits that energy in much shorter time frame), regular hurricane generates in a minute same energy as 10 kT nuke. Based on that, I think Sibling could straight up tank WW2 nukes, or simply utilize pressure fabrials that would mostly block the blast wave. Maybe at most once a minute or two, but that is more then enough.

It was still 150 meters away from center, that is relatively side-ways (if not completely). And again, Urithiru has far thicker walls than that, and is about as large as modern skyscraper, if not larger. There is a reason why most anti-nuke shelters are built into mountains/hills, it makes them practically immune to nukes, unless you drop several of them on the same spot. Some of it not all, that fireball is relatively short lived, and rock has quite large heat capacity. Edit: Melt cavity for underground testing (where explosion energy has nothing else to do but push and melt stone) has radius that goes like 3rd root of kT of energy. So even if the nuke was inside Urithiru, at most rock in radius of 11-33 meters would be melted. And rock would get crushed only inside radius 80-110 meters. Of course, since Urithiru has holes, a lot of that explosion energy would instead be deposited in shock wave, and travel through those 'escape' holes, so actual radius of melt and crush would be far lower. Explosion on the outside of Urithiru is basically guaranteed to not melt any rock, unless it would be directly against the side of Urithiru (which as you note is unrealistic precision). It would probably crush some of the outer walls, but I think anything more than 10-20 meters deep would survive basically intact. Which would just make it even more structurally sound. Basically, to properly attack Urithiru you requires something like bunker buster, which nukes are not. Windrunners do seem to regularly patrol, since Fused intentionally mimic those patrols in RoW. And detection could also be done with alerter fabrials, though they would have to know what to look for. That is more feasible target.

I mean, Hemalurgy changes spirit by definition, since it spikes additional parts into it And notably, Koloss cognitive aspect reverts back to human after dying, and does not remain Koloss after death, suggesting the changes to spiritweb aren't persistent, and are more due to presence of spike in the body, so once Cognitive aspect no longer has valid Connection to PR, spiritweb reverts to original state (or close to it)

It would at best destroy few outer rooms, most of Urithiru would be fine. This building (https://en.wikipedia.org/wiki/Hiroshima_Peace_Memorial) was just ~620 meters from the detonation, and considerable parts remained intact. So if building made out of bricks and concrete, can remain standing, building that is basically carved into mountain with far thicker walls (that are just one piece, not several connected by weaker bonding material) will be fine. I don't think Urithiru is really built with weight bearing columns and such, it is more like carved into the mountain. The stones on 14th floor remember being the original mountain, and the building seems like one giant piece with tunnels. Downright impossible more like. Bombers are slow and cumbersome compared to Windrunners, bomb can be in principled lashed away (unless Aluminum plated), or the Windrunner can carry Elsecaller who could soulcast air in front of bomber into stone.

I doubt this would work, since everything has Identity (and it seems to be innate property of Investiture), and blanking Identity seems to require either specific Invested art (like Feruchemy, and even that is not full blanking) or relatively special condition. Intent only helps shape what exactly you will get, but won't allow you to do things out of nowhere. Hemalurgy only rips away pieces of spiritweb, it does not change those pieces in any way (as far as we know), so Intent would not let you do this blanking.

Transparent 'aluminum' is a composite ceramic material, and as seen from Scadrial, alloys and composites don't necessarily share properties of the original material (e.g. Duralumin, which is 95% aluminum has no Investiture blocking properties to speak of). In this case, aluminum forms less then 50% (by number density) of the material, so at best it would work as extremely flawed sphere, so it would leak out.

Unknown. We have not seen anyone who had more than 1 thing spike out.

It is being used in the frame, at least in the conjoiner/reverser case. It is possible that just aluminum cage alone would simply not do anything, being inert to Investiture.

We know a couple of the aluminum effects in fabrial, and it seems to be neither of these. In conjoiners aluminum in the metallic casing is used to isolate planes of movement, so e.g. only horizontal movement is transferred. (This is used in Rysn's 'wheelchair') Reversers work along pretty much the same principle as conjoiners, so it would work the same way there. For attractors/repulsors, aluminum would serve to shield certain direction from effect, so instead of omni-directional push/pull you can get directed effect (https://wob.coppermind.net/events/509/#e16021) For others types, we will have to wait and see for back-half of SA I expect.

I also think Herald of Heralds would take this, Surges are the same, and while Yelig-Nar has possibly crystalline armor, Herald of Heralds can cut right through that with Honorblade. Additionally, Herald of Heralds would be unchained Bondsmith, which I don't think would be replicable by Yelig-Nar.

That would be possibility, though for Shinovar it would be dependant on what Soulcasters they have access to. But proper alloy might be possibility as well, even if it will not protect as fully as pure aluminum. I can't recall precise quote, but I think either in O or WoR, Pattern mentions that current spren population is larger than during Recreance. Not 2000 Honorspren in 5000 years, only around 3000 (4500 to Aharietam, but Recreance is only 2500 after it). Also during those times Honor was alive, so presumably there was less Investiture. There is a WoB (https://wob.coppermind.net/events/186/#e4129) that spren serve as release valve for the power after Honor was splintered. So, 2000 years would be sufficient to nearly replace the numbers anyway. There is enough Honorspren to fill the arena in Lasting Integrity at least twice over (on the second day of trial most of the audience is different, as those who would be sympatetic to Adolin are forbidden entry), and the arena can seat couple hundred, so the 800 is basically near minimum, and would require all Honorspren to attend. And Honorspren waged war in Shadesar on the other Radiant spren, if there would be only 800 that would not be war, but barely a skirmish. So they must be relatively sizable on their own, and relative to other spren as well. And Lightweavers can easily create mud through Soulcasting, while hidden by ilussion. Or Stoneward/Willshaper can hide in hole they shaped, and render the rock liquid right under tanks.

Not pure aluminum, pure aluminum would be worthless for planes. Planes were made from alloy, and those don't necessarily share Investiture resistant properties, only some do. The only way they could have access to CR is Honorblade, or Radiant, though Oathgates. Asumming Radiant joins WW2 side is against the setup I would say (if anything Rosharan side would have easier time bribing WW2 side, just sneak in Lightweaver who will soulcast gold bribes on demand). Windrunner in plate with machine gun anyone? And you forget that Sibling (and Stormfather) can simply ask Oathgates spren to lockthemselves, so Oathgates are no go. And Perpendicularities are inaccessibly, one is moving possibly in Hurricane, the other is inside lake. And they are not large enough to fit vehicles/planes. So no, CR will remain domain of Rosharan side. So is Roshar, and they can spy and bribe far easier than WW2 side. If there are 2000 full Windrunners, then there would be at minimum 10000 Windrunner squires alone, they have squire resonance with most having more then 5 squires (even Lightweavers have 3-5 squires). Most likely 2000 full Windrunner results in 15-20k squire Windrunners, so just Windrunners would be 17-22 thousand. Full Stonewards were similarly numerous, but had less squires (Lightweavers have 3-5, so those can be a good estimate), so possibly 10k Stonewards. So just these two orders give more than 25k Radiants, so total number can easily go over 50k Radiants. And 2000 full Windrunners were during Recreance, since then both human and spren populations have exploded, so these numbers likely underestimate. Pure aluminum completely sucks as armor, and while there would be no tanks shooting at it, lashed hunk of rock will do the trick against that. Not to mention soulcasting/stoneshaping terrain under the tank/artillery, there aluminum will be no help at all. Without Oathgates for travel (which can be locked as mentioned above) they will have bad time getting all that equipment across the mountains + they will be incredibly sensitive to supply lines. Alethakr was the country with most soulcasters, so without those the Shin army will be utterly reliant on long supply lines for all munitions and gas. And long supply lines don't work well with two regular Hurricane storms.

For casual travel when carrying non-Windrunners they move at ~300 mph (Rosharan miles) which is about 350 mph in earth miles. And this is only for travel, not combat, while carrying people who lack their control over wind/air. We have also seen them outrun Highstorm near its peak power, which is moving at more than 400 mph (Rosharan), so ~460 mph earth miles. And this is all prior to having Shardplate available, which goes in hand with better control over windspren, which can be utilized to create pressure corridors sufficient to stop Highstorm level winds as seen in RoW. So speed wise Windrunners can go toe-to-toe with WW2 fighters, and most likely go beyond them especially with Plate. On top of that they are far smaller, and far more maneuverable. The only issue is lack of ranged weaponry, outside of carrying some small rocks/pieces of metal. From WoBs we also know that Windrunners can potentially travel between planets, so their speeds can reach quite considerable heights.

Roshar. On Roshar they don't have to worry about Stormlight, they can get it on-demand, so the only limitation of them falls away. Roshar has discovered anti-Investiture weapons (which are anti-matter weapons), and with some RnD they can scale those up, so soon they will have atom bomb equivalent, and they can easily make more. (though they would probably defeat WW2 side faster than that would happen). Thanks to Fused, Roshar has immortal soldiers, though only some are sane enough to fight (maybe Kaladin could get few more to shape with his therapy powers). Roshar can heal radiation poisoning trivially, and WW2 side has limited number (I am assuming they have ~10 atom bombs at most, and relatively small scale at that), and can deliver them only by air. However, Windrunners + Skybreakers are more maneuverable than WW2 planes (and far more than bombers), so Roshar has air superiority. Roshar can trivially sabotage any weapons system, or manufacting facility of WW2 side, or poison food supplies (soulcasting from CR, which is easier to do even). Drop one Windrunner in plate in the middle of a camp, and he will destroy every piece of equipment there and take next to no damage (Shardplate would resist bullets well per WoB). Bullets are useless against any team containing at least one Windrunner, since they can infuse some hunk of rock/metal with Reverse Lashing, and then just put that a bit to the side, and all the gunfire will go to that. Roshar has mobility advantage (Oathgates), and has infrastructure (which WW2 side does not, no oil to fuel them or supply lines for munition). WW2 side has no protection against fabrial weapons, or Shards, or Surgebindings. Munition/weapons/fuel will be soulcasted away, and replacing it takes a long time. You cannot shield against fabrials that draw blood away from your body, or those that cause so much pain you get paralyzed. Edit: I would also note that Roshar is not as far behind as some think. The predominant culture (and focus on magi-tech vs real world tech) obfuscates it, but they are technologically only very little behind Era 2 Scadrial, just developing in different direction shaped by available resources. Their medicinal science is late 19th at least with some areas possibly more advanced. Their physical science is a mix of early 19th to early 20th century. Their transportation is right on break of 19th and 20th centuries (lifts, flight, flying wheelchair) with car equivalent probably not too far behind (they have all the pieces available right now). Lack of fossil fuels meant that it took fabrial revolution to start developing anything in this area, and it took additional advancement with understanding of aluminum+Connection interaction that allowed it to move forward. Communication technology is using principles more advanced then we have in 21st century, effectively having quantum connections, though using them only in telegraph equivalent with analogue of switchboard station, again late 19th century technology. Thanks to Urithiru, they can study more advanced fabrials (such as air vent system, early 20th century; sliding doors, middle 20th century) to push their technology further. Mining and manufacturing was distorted by presence of Soulcasting, so they had little incentive to research in that area. Taken all together, they are comparable to civilization in late 19th/very early 20th century.

Remember, Hemalurgic spikes are relatively severely limited in how much Investiture they can hold, they are far less Invested then metalminds. Single spike would not take much away from Vessel, certainly not enough to do any real damage. That is indeed the question. I think it is not much power, so Hemalurgy (without advanced hacks) will be on 'people' level only, not Shard level. Part of the reasoning is that Hemalurgy can be used to do similar things to Bondsmithing, and that is intentionally heavily restricted art (both in-world, and by Brandon). So I doubt Hemalurgy, which can be practiced by anyone, will approach anywhere near that scale of power. Shards don't grant permission to access Invested art, if you fulfill the requirements (in this case metal + donor + Intent in line with Ruin) then you get power. Shard cannot prevent that. If anything I think it is relatively fixed amount of power. You rip of chunk of spiritweb, and most time the chunks are relatively 'same sized', so more power is not necessarily required. Doubtful, in no Invested art do you get more Investiture available, simply because you want/need it to accomplish something. Either amount of Investiture is fixed (Feruchemy, Allomancy, Forgery) or it uses external source (Awakening, Surgebinding). From what we know of Hemalurgy, it falls in the scope of fixed Investiture. At this stage, there are only two non-Shard entities that are confirmed to hold power on similar level, and can meaningfully interact with Shards/Vessels and in both cases Shards are directly Involved anyway.

I doubt that would be possible, if ordinary metal with proper intent could wound or kill Shardic vessel, why would Similarly, Vessels (and Hoid) fear Nightblood, but neither seems particularly afraid of Hemalurgy, so I strongly doubt that Hemalurgy could do any lasting damage to either. When they are Vessel, their souls are merged with Shard, so spiking it out would be difficult (kinda like spiking Spren Bond). Hemalurgy is still Invested art, so whatever happens through it is powered facilitated by Ruin/Harmony. So doing something with it that damages Vessel is doubtful, since it took the single most Invested object in Cosmere to do that.

Ah, impatience, cause of human sacrifice since Era 2

Not sure if I would call murdering hundreds of people (or permanently crippling them) the best way to create object that can resist Shardblade For single sword, you would maim thousands. Metalminds seems like the better option, though more time-intesive.

Hmm, good point on the Set experiments. Though notably, per those same experiments, Spike becomes fully charged after 20-30 people, and that is when they take only 'vestigial' part of soul, not what regular spiking would do. So there is an upper limit to how Invested a spike can get, and it is not that much. If size is a factor in spike, then the Spike Set used was 6 inches long, large needle. Regular needles that are at most inch long weight around 1 gram, so this one weighted at minimum 6 grams. So regular sword would be ~200 times the size, and so could hold vestigial Investiture from ~4000-6000 people, before it would become impossible to Invest it more using Hemalurgy. Now there is a question of what is the ratio between vestigial Investiture from a single person, and Breath, because it could possibly be less than 1000 Breaths required to just Awaken a sword. Sure that could work. Nahel Bond requires is between Concious entities already, so that would not be happening. If anything I think it would hinder the process, since the Investiture would then be Connected to the wielder and his Conciousness (sort of like what happens with Shards). Probably not, even creation of the Soulstamp is act of Invested art (creation of soulstamp away from Sel requires Invested Ink to work). Blacksmithing a sword is not like that at all.

You cannot re-use Hemalurgic spikes, not unless you somehow strip them of Identity, and even then it is not as easy. Plus you need to hit bind point to perform Hemalurgy, regular old stabbing/slashing won't be enough. The only instance of on the fly Hemalurgy were done by people guided by Ruin, all others had victims restrained, and Hemalurgist possibly used Atium to guide spike even then (Inquisitors). So spiking someone in battle is going to be super difficult. So there would have to be multiple hoops to jump through before that can happen. Also, Investiture taking on Conciousness of its own takes a lot of time, possibly hundreds if not thousands of years (depending on when exactly Dor was formed). Nightblood was also created via Command with Intent, neither of which is present in creation of this sword (plus there was possible Shardic intervention in its creation). Doubtful this blade could absorb Investiture on its own, since seemingly the other Nalthian blades does not do that. It could become eventually sentient, but would not get other powers out of it I expect. Even Nalthians blades required complex visualization to work in the first place, and some of the powers can be side-effect of interaction of visualization/Command/Shardic influence. Most likely no.

It could help with proprioception, though it is questionable if that is affected by A-Tin in the first place. (though seeing Spook it might be). But you would still be basically unable to perceive your surroundings. I don't think so. Savantism is very specific kind of transformation of spiritweb, sort of limited sliverism. As you use given power, the spiritweb adapts to the power, and can no longer function as usual. So I don't think it would do anything to heal spiritweb in any way. Sole exception being A-Aluminum savantism, which can help 'purge' unwanted effects, though I doubt that includes even minor healing of Hemalurgic wounds.

I don't think it would overwrite Tin savantism, it would just end up with him being Savant in both. TLR was Savant in all the metals (and possibly in Feruchemy as well), so individual savantisms don't overwrite one another. You just stretch your spiritweb in different ways. So end result would be Spook that is effectively blind/deaf/without senses (since they can no longer burn Tin) which would combine with Pewter Savantism, where he could not feel pain nor exhaustion. So you have someone who is A-pewter burner, without basically any senses.

There is no spatial dimension in SR, so there is no 'distant' there. Based on that Lashing could possibly still work.

I think just the fact that you can soulcast things into Aluminum is relatively good evidence of it having Cognitive representation. Otherwise it would be basically convincing object to 'kill itself', which would be a hard sell I imagine. And heavily Invested objects mimic at least some properties of aluminum (cannot be pushed/pulled, cannot be seen with steelsight, interfere with Investiture, allow blocking Shardblades, etc.), and those still have CR and SR representation. And Aluminum is stated to resist Soulcasting (and other forms of Investiture trying to change it, https://wob.coppermind.net/events/171/#e8306). If it had no CR representation than it would not resist, it would be flat out impossible to change it via Soulcasting.