How in the bloody world did she do that? A biological look at blood Soulcasting


A long, long time ago, in a galaxy far away, it was pointed out on Shardcast that I am rather bothered by the mechanics of blood Soulcasting. Or more specifically, how it is used to save Shallan’s life during The Way of Kings. I have a background in molecular biology and have spent several years working with blood products, so to have some fun, I decided to put my nerd cap on and combine two of my passions.

I would first like to preface this article to say that Brandon has been clear in the fact that he has limited knowledge of blood. The way he uses blood Soulcasting in WoK, for all intents and purposes, is perfectly fine for a book not about blood transfusions. I find for me personally, the scene in the hospital pulls me out of the story, but it shouldn’t be expected (and I certainly don’t expect it) of Brandon to write something supremely in depth and medically accurate. The basics will do. Besides there is an answer as to why this works and the answer is spiritual mumbo jumbo.

After Shallan is poisoned by Kabsal, Jasnah saves her life by Soulcasting Shallan’s blood to remove the poison. In doing so, Jasnah is introducing new blood into Shallan’s body (in essence, providing a blood transfusion) that does not match Shallan’s system. This was a risky choice by Jasnah, not just because of the dangers posed by Soulcasting, but also by the dangers associated with mismatched blood transfusions. The probability of Jasnah getting the make up of Shallan’s blood correct and causing no reaction is very small. 

Blood is complex. Although we think of it as a homologous unit, it is made up of different parts, each of which perform different functions in the body. As well as this, the type of blood we have can be vastly different from person to person and if the wrong type of blood is given to someone they could have a severe reaction, or in the worst case, die.

It is unclear what the exact nature of blood types is on Roshar, though I’m going to take the ‘eight types’ spoken of by Jasnah to be the eight major blood types in real life; O+, O-, A+, A-, B+, B-, AB+, AB-. Brandon has confirmed the existence of Rhesus factor (Rh) (which is denoted by the +/- on blood typing). Knowing that Rh exists in Stormlight, it’s logical to expand that the other main blood types also exist. Roshar has some knowledge of blood typing, although it is not extensive of modern day typing.

Blood Grouping
The two most commonly known groups, as well as the major groups when considering transfusion, are the ABO and Rh groups (+/-). Your ABO is particularly important when being given someone else’s blood; if you are given the wrong ABO group it can lead to a rejection of the donated blood by your immune system. When transfusing blood your ABO group is of utmost importance, however, it is not the only blood group that needs to be considered. 

Currently, there are 34 known blood group systems, comprising of over 300 molecules that could be found on the surface of your blood cells. Most of these systems give rise to rare blood types, where you either have a molecule that most people do not, or vice versa. While the specifics of each of these minor systems are not important, the variety of combinations that they give rise to creates problems when giving blood from one person to another. Except in life threatening situations, patients will almost always be checked before being given blood to minimise the risk of reaction. 

Most people when they think of universal donors think of O- blood. Indeed it is; but only in the case of red blood cells. Blood is not one substance, it is a mixture of different cells. ABO receptors can be found on red blood cells, while antibodies are found in blood plasma. ABO is less important for another component of blood, platelets, however, in this case HLA receptors need to be considered. HLA is also a factor for a fourth component of blood, white blood cells.

diagram-showing-composition-blood_1308-36054.jpg

Red Blood Cells
(Risk: patient cells attacking donor blood)
O group has no blood receptors on red blood cells - if transfused it won’t be attacked by the patient’s body, hence O group is the universal donor, as it can be given to anybody. Conversely, AB is the universal recipient because it has both A and B receptors - if given to a non-AB patient, it will always be attacked by the recipient’s immune system.

Plasma
(Risk: donor blood attacking patient cells)
O group is the universal recipient - it contains antibodies against both the A and B receptors and will attack patient’s cells that have these receptors. Conversely, AB is the universal donor - it produces no antibodies and cannot attack patient cells. 

Platelets
(Risk: patient cells attacking donor blood)
ABO is less important when considering platelets as these receptors are only weakly expressed. Instead these cells strongly express HLA receptors, a crucial receptor that leads to an immune response, which may or may not be shared between donor and recipient. If they are not shared, and the patient has developed antibodies against these HLA receptors, the transfused platelets will be destroyed rapidly, leaving the patient at risk of serious bleeding. 

White Blood Cells
(Risk: donor blood attacking patient cells and vice versa)
White blood cells are immune cells. Their make up is also based on HLA receptors. If these receptors are not shared then the transfused white blood cells can attack the patient's cells.

In modern medicine, blood is separated into components (red blood cells, plasma, and buffy coat [platelets and white blood cells]) which makes it easier to prevent reactions during transfusion. Jasnah, to remove the poison, would need to replace all of these components of blood at once. 

  • An exact ABO match would be needed to prevent an immediate reaction due to whole blood or plasma donor mismatch. 
  • Enough of a HLA match would need to exist to prevent platelet destruction and risk of uncontrolled bleeding. 
  • The white blood cells could cause a major problem if detected as foreign - if donor cells attack the patient or vice versa, this could cause a delayed reaction. 
  • This does not account for any of the other blood systems or blood receptors that could cause either immediate or delayed reactions. 

Blood is easier to make than other organics because it is an Essence, however, Jasnah also admitted that she is not good with Soulcasting blood which made the endeavour extremely dangerous. Replacing someone’s blood via Soulcasting seems like a difficult enough task for someone extremely skilled in this type of Soulcasting, let alone someone who has difficulty with it. 

How then, does Jasnah successfully do this? To inject our regular case of spiritual mumbo jumbo, it is likely the case that she is not just Soulcasting blood, but instead Soulcasting the poison to specifically be Shallan’s blood, based on her spiritual ideal. Hence negating all of these biological problems.  

This is an adequate answer that I have always disliked. But that’s just me. I am very excited to see how Brandon further explores interactions between human biology and his magic systems both in SA and also in the Silence Divine (fingers crossed that this is a story he gets to write).

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This is a phenomenon that reappears in every Surge's applications. I've gone into some of them in this thread. To melt stone and make a staircase like the Aharietiam Stoneward did in OB, you need to fundamentally alter the coefficients of molecular bonding between all molecules in an specified area, apply energy balance effects to maintain system temperature, and then generate an infinitely complex field of forces to act on each molecule individually to shape your object's boundary. Even a relatively straightforward force-manipulating Surge like Gravitation has its funkiness: the "half-lashing" leaving you weightless and the way the Reverse Lashings work imply changing the direction of existing gravitational forces; but nothing's shooting off into space due to the rotation of the planet, so the magic's math is always balancing that out. And there's the "spiritual link to the ground" mentioned in the Ars Arcanum as a fuzzy explanation of what exactly is affected and why.

Rosharan magic is fundamentally more complex than many of Brandon's magic systems. It's the idea of "causes" vs "effects." Allomancy from Mistborn is an excellent example of "causes" - a narrowly specified magical phenomenon which can be applied in different ways. Steelpushing may be tough to sort out, but at the end of the day, it's the addition of an new force within the existing system of kinematics. Surgebinding is an "effect" - it's going to accomplish something particular, as it is defined, and anything that stands in its way is going to be accounted for in the background. TVTropes even has a page for this concept: Required Secondary Powers.

Brandon hangs a lampshade on all of this with Surges being based in perception, not just in-universe fundamental physics:

Quote

Argent

My understanding of the... spren is that they grant powers based on what they understand to be fundamental? Ish?

Brandon Sanderson

Ish. I wouldn't 100% go with that. I would say these are the fundamental forces-- They aren't as scientific as our fundamental forces, but I would say it's more than just what the spren view and what the humans view in that case. But they are more philosophical than scientific, in cases.

Argent

Other cognitive beings, could they-- A spren on Earth. Would it grant electromagnetism surge, for example?

Brandon Sanderson

That, I would say yes.

Skyward Chicago signing (Nov. 16, 2018)

Mistborn's magic systems are like Microsoft Excel. You get your library of functions, and you can use them individually or in combination to build your nice spreadsheet. But you need to know how all of Excel's functions work to use them. Allomancy has steelpushing, Feruchemy has weight-changing; they're both handy individually, but put them together, and there you go, you've got tricks built up from these building blocks.

Stormlight's magic systems are like Facebook. You can upload pictures, create groups, etc.; but you don't need to know how Facebook is coded or how its databases work. There's a user interface that has been built into the website that lets you accomplish what you need to. Surgebinding's "user interface" was, first and foremost, developed by the author; there must be an in-universe mechanism for accomplish it, presumably from the magic's Shard, but the concept is required by the kind of magic Brandon wants to put in his books.

I wouldn't say Stormlight's magic is necessarily limited by this contrast. Dalinar, especially, has been doing... browser extensions, I guess? I don't know how to continue the analogy. There are ways to break the system, but the existence of the system itself means that you can do biology-related effects without being a molecular biologist, or gravity-related effects without being a quantum physicist.

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All arcane methods seem to prefer to act on a whole object. So when Jasnah replaces Shallan's blood, she replaces all of it. In that case the existing antibodies will not matter, won't they? They are replaced. If the blood is internally consistent you should not see an immediate reaction.

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Chaos

Posted

12 minutes ago, Oltux72 said:

All arcane methods seem to prefer to act on a whole object. So when Jasnah replaces Shallan's blood, she replaces all of it. In that case the existing antibodies will not matter, won't they? They are replaced. If the blood is internally consistent you should not see an immediate reaction.

I think the real problem is that Brandon had a WoB about there being a "universal donor" which... really doesn't work: https://wob.coppermind.net/events/322/#e9237

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9 hours ago, Oltux72 said:

All arcane methods seem to prefer to act on a whole object. So when Jasnah replaces Shallan's blood, she replaces all of it. In that case the existing antibodies will not matter, won't they? They are replaced. If the blood is internally consistent you should not see an immediate reaction.

The body would respond eventually - a lot of the immune system isn't found directly in the blood and would probably react pretty quickly. It wouldn't be immediate but it would happen in short order. 

What it could be, is if everything is replaced - blood, tissue, immune system - then it could technically work (and this is just named 'blood' Soulcasting for simplicity), though if it all comes from a single donor (god I dislike that wob) then eventually everyone would die of disease as they could evolve to only have to avoid *one* type of immune system. 

11 hours ago, Pagerunner said:

Mistborn's magic systems are like Microsoft Excel. You get your library of functions, and you can use them individually or in combination to build your nice spreadsheet. But you need to know how all of Excel's functions work to use them. Allomancy has steelpushing, Feruchemy has weight-changing; they're both handy individually, but put them together, and there you go, you've got tricks built up from these building blocks.

Stormlight's magic systems are like Facebook. You can upload pictures, create groups, etc.; but you don't need to know how Facebook is coded or how its databases work. There's a user interface that has been built into the website that lets you accomplish what you need to. Surgebinding's "user interface" was, first and foremost, developed by the author; there must be an in-universe mechanism for accomplish it, presumably from the magic's Shard, but the concept is required by the kind of magic Brandon wants to put in his books.

I really like this analogy. I haven't thought about the distinctions between the two magic systems much and have been conflating them in my brain to be built in similar ways. But at the same time, I would say I have an inherent bias towards imagining Surgebinding like the Metallic Arts, simply because I started with Mistborn. 

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21 hours ago, Chaos said:

I think the real problem is that Brandon had a WoB about there being a "universal donor" which... really doesn't work: https://wob.coppermind.net/events/322/#e9237

Well, such a donor does not exist, but you could define it, couldn't you?

  • red cells should be 0-
  • the plasma should have no antibodies, that is it should be AB+
  • the platelets need to match the leukocytes

Whole blood transfusions from a 0- donor were done in the early 20th century, weren't they? It may not be ideal, but we are talking about a survivable, not a good treatment.

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As a writer, I'd just like to say that it is freakin really really hard to work with science and magic. To an average reader, the scene with Jasnah makes pretty good sense.

Nothing will ever be perfect, unfortunately (Except for a spiritual ideal of something!) and so if Brandon went in depth on how soul casting works with blood, then many readers would be left confused.

However, you do make very good points in this article. If I ever write a magic system with blood I will try to do my research!

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Subvisual Haze

Posted

I imagine soulcasting blood is a lot like Stormlight passively healing wounds in general.  There's a template of how things "should be" in the cognitive realm and the magic works to replicate that into the physical realm.

Jasnah is probably preforming a rudimentary form of hemodialysis when she is soulcasting blood.  Take out a certain non-lethal volume of poisoned blood -> replace it with "normal blood" (using Shallan's cognitive image of a healthy self to guide the Stormlight/Soulcasting of what her usual non-poisoned blood would be like).

Just like with dialysis or normal glomerular filtration of your blood by your kidneys this would be a time consuming process and require multiple "cycles" to progressively cleanse the blood as you can only remove and filter a fraction of the total volume at a given time.

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On 4/19/2020 at 4:12 AM, Oltux72 said:

Well, such a donor does not exist, but you could define it, couldn't you?

  • red cells should be 0-
  • the plasma should have no antibodies, that is it should be AB+
  • the platelets need to match the leukocytes

It could just be defined that these things aren't from necessarily one donor and instead just exist as the universal types in separate forms and blood Soulcasting can just draw from these pools at the same time and combine them. In that case you could just drop the lymphocytes, they can do more harm than good. 

On 4/19/2020 at 4:12 AM, Oltux72 said:

Whole blood transfusions from a 0- donor were done in the early 20th century, weren't they? It may not be ideal, but we are talking about a survivable, not a good treatment.

Fun fact, whole blood transfusions are occasionally still used if someone is bleeding out, as what they need, more than anything at that given time, is just more blood to stop exsanguination. It comes with a host of risks, but the alternative can be almost certain death so the risk of future complications are worth more than the immediate danger to a patient's life. 

Though, at least from what I've read, it's generally only recommended to give group to group whole blood transfusions even in these circumstances (A to A, O to O) and if the person's blood grouping is unknown (and there isn't time for crossmatching to find out) to give separated universal products because of the potential complications to try and limit known complications. 

On 4/20/2020 at 2:08 AM, MysticLotus said:

As a writer, I'd just like to say that it is freakin really really hard to work with science and magic. To an average reader, the scene with Jasnah makes pretty good sense.

Nothing will ever be perfect, unfortunately (Except for a spiritual ideal of something!) and so if Brandon went in depth on how soul casting works with blood, then many readers would be left confused.

However, you do make very good points in this article. If I ever write a magic system with blood I will try to do my research!

I imagine that even in a hard sci-fi novel it would be difficult to get the science 100% accurate - the nice thing about fiction is that magic can be used to cover the blurry spots. As I mention in the article, I don't expect it to be perfectly accurate, and with it having an aspect of magic, I doubt it ever could be. I never intended this piece to be a criticism of Brandon's work, more a combination of my interests and a chance to share some extra understanding into the mechanics of how blood works (and to have something I can easily link to in the future when asked about this).  Even if the scene doesn't work for me personally, it doesn't mean by any stretch that the scene is bad or needs to be changed - it works for most people and that's what matters.

9 hours ago, Subvisual Haze said:

Jasnah is probably preforming a rudimentary form of hemodialysis when she is soulcasting blood.  Take out a certain non-lethal volume of poisoned blood -> replace it with "normal blood" (using Shallan's cognitive image of a healthy self to guide the Stormlight/Soulcasting of what her usual non-poisoned blood would be like).

Just like with dialysis or normal glomerular filtration of your blood by your kidneys this would be a time consuming process and require multiple "cycles" to progressively cleanse the blood as you can only remove and filter a fraction of the total volume at a given time.

I think Jasnah mentions to Shallan later that she had to Soulcast her multiple times as well. I would agree with it being similar to hemodialysis - if she's putting in new blood she would need to be removing some as well to prevent circulatory overload. 

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Nitpicking

Posted (edited)

I just watched Shardcast on YouTube, and followed the link to this article. I was all ready to correct the biology (I'm a biology teacher by training), but ... well, LadyLameness is actually an expert and there was nothing to correct. Nice job.

I do feel obligated to point out that since transfused leukocytes are not only useless to the recipient, but actively damaging in some cases (as our esteemed author says), they're generally removed in a process called "leukodepletion." I used to work for the company that invented leukocyte depleting filters for transfused blood.

Also, consider that Shallan was actually a Radiant when she cut herself open and started to bleed out. She didn't remember it consciously, but she had manifested her Blade years before. Even if the Soulcast blood harmed her, she might have been able to heal herself with Stormlight without realizing it, just as Kaladin and Dalinar both did.

Edited by Nitpicking
spelling fix
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2 hours ago, Nitpicking said:

I just watched Shardcast on YouTube, and followed the link to this article. I was all ready to correct the biology (I'm a biology teacher by training), but ... well, LadyLameness is actually an expert and there was nothing to correct. Nice job.

Aw thank you Nitpicking. :lol: I was actually very worried that I might get something wrong - transfusion is an area that I've worked in but not my main field of study, so I felt very much like I only had surface level information. 

2 hours ago, Nitpicking said:

I used to work for the company that invented leukocyte depleting filters for transfused blood.

This is super neat! 

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I'm really late getting around to reading all this and responding.

On 4/21/2020 at 10:16 PM, LadyLameness said:

I think Jasnah mentions to Shallan later that she had to Soulcast her multiple times as well. I would agree with it being similar to hemodialysis - if she's putting in new blood she would need to be removing some as well to prevent circulatory overload

Jasnah says she had to Soulcast multiple times because Shallan's body kept absorbing the poison.

Also my immediate thought was that, given what we've seen of how Soulcasting works:

I think Jasnah told Shallan's poisoned blood to become what it was without the poison, as it should have been able to remember what that was like.

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