The science of killing your characters

research-at-work               *** This post may contain some detailed and disturbing descriptions***

I spend a lot of time thinking up ways to kill people. Normally this might classify me as a psychopath…if I weren’t a writer. Let’s just hope the FBI makes that distinction if they ever get a glimpse of my search history.

This is a very important subject for writers to research, not just to add realism, but because death, or rather the avoidance of it, is one of the most common motivations for characters. Pretty much every adventure, horror, mystery, tragedy, and drama story uses death or fear of death to some degree. Death is, understandably, the greatest universal fear. It means the end of everything (unless your story contains elements of the afterlife), and there is no coming back from it. Even the bravest of heroes and heroines are cowed by the prospect of imminent death. It makes the bravest of men and women weep and pray to be spared, and it can provoke irrational and reckless actions in the most learned and patient of people. It is the most useful tool in the writer’s toolbox for creating suspense, surprise, and horror.

When writers are given the ever-important task of describing the stakes for their main character, most of them are common iterations of the word “death.”

  • Save the _____.
  • Survive the_____.
  • Fate of the _____.
  • Destroy the _____.
  • Loss/end/demise/etc.

Death is often featured in the opening of a story to spark the initial conflict, and it can be used to conclude the conflict at the climax. It is important then that death be portrayed accurately when it finally does strike, especially in these two all-important scenes.

I watched the first few minutes of a movie the other day and I couldn’t bear to watch any more than that. The victim in this opening scene of the movie had a huge hole punched through their chest. Despite their heart and lungs likely being destroyed, the person was able to spend the next couple minute saying their farewells. I’m sorry but you can’t talk without lungs, nor can you stay conscious for more than a few seconds when your heart is turned into mush. Unlikely deaths can cause an audience to laugh or roll their eyes, which is often not what an author is going for.

In this post, I will discuss the most common types of death featured in fiction. It is, by far, my longest post and pretty heavy on the science; my apologies.

Death by poison.

If your protagonist or antagonist has to kill someone without casting blame on themselves, they will either hire an assassin, wear a mask, or choose poison as the murder weapon. Sadly, poison has been a bit overused in fiction as a means of causing death, and often it is used inaccurately. The poison itself will only be effective at the right dose, in the right vehicle (solution, powder, etc.), and by the right mode of entry (breathing, eating, drinking, injection, etc.), so it is important to do research. Simply coating a bit of it on an arrow tip will probably not work.

Also, almost anything is considered a poison at the right amount. Put a tiny bit too much harmless potassium in someone’s IV and they will go into cardiac arrest. Since potassium levels naturally spike after death, such a poisoning would be impossible to detect. There are a lot of poisons, so for the purposes of this section, I will focus on the ones that are interesting to me.

Succinylcholine is a common one used in fiction. This paralytic is often toted as the best to use if your characters want to get away with the murder. First thing to appreciate about this drug is that it has to be injected into the muscle or vein; eating it is useless. This poison functions by imitating a common neurotransmitter, acetylcholine, which is how nerves tell muscle to contract. When injected with this paralytic, classified as a depolarizing paralytic, the muscles contract and spasm uncontrollably and prevent the muscle from repolarizing in order to undergo subsequent contractions. The patient is paralyzed within a couple minutes and dies within a few minutes after that because they are unable to breath. It is nearly undetectable because it is quickly broken down into choline and succinate, two molecules found in abundance in the body.

It might surprise you that the poisons cyanide, azide, and the gasses carbon monoxide, nitric oxide, and hydrogen sulfide all work in the same way, by inhibiting Complex IV of the electron transport chain in the mitochondria. This protein is the main reason why we need to breathe. Almost all the oxygen you take in will be used by the mitochondria by this protein, which dumps 4 electrons onto oxygen to make water. This is the final immensely favorable reaction required by the mitochondria to drive the highly unfavorable pumping of protons into the inter-membrane space of the mitochondria. Once an electro-chemical gradient is established, those protons pass through Complex V to drive the production of ATP, the molecule that ‘powers’ most cellular functions. With ingestion of sufficient cyanide or azide, and breathing of the gasses, the victim will die by lack of energy production, a complete suffocation of all the individual cells. It may interest you to learn that rigor mortis, the stiffening of a body at around 12 hours after death, is the result of the body’s muscles finally running out of ATP. In the muscle, ATP is required to relax the contractile machinery and to keep calcium from constantly flooding into the cell and causing contraction. The relaxation of the body afterward is due to the degradation of the myofilaments causing the contraction. During my day job I study mitochondria in muscle, so I can tell you that there are hundreds of potential inhibitors of mitochondrial function to chose from.

Botox is not simply a way to prevent wrinkles, it is also the most toxic poison known to man. Produced by the bacteria Clostridium botulinum, this protein prevents the release of acetylcholine, often causing death by rendering the victim unable to breathe. But if small amounts of this toxin can cause death, why is it used in cosmetics and medicine for all kinds of diseases and conditions? It is all about containing the spread of the toxin. If an injection hits a vein rather than an intended muscle, you better hope someone can put you on life support. The muscle weakness can last for months.

Last but not least, Russel viper venom. Of all the millions of poisons to choose from, why this one? Because I find it fascinating. The venom is a direct activator of Factor X in the blood, the enzyme that converts prothrombin to thrombin and activates coagulation. In short, it turns your blood into a thick sludge. This can, ironically, cause you to bleed uncontrollably because all your clotting factors and platelets are used up.

I haven’t gone into a lot of symptoms for these poisons, primarily because there are so many of them, but I do advise writers to look up dosage, symptoms, and cause of death to make sure they get it right. There are many other poisons, but this post is already going to be too long. If you have questions about what poisons to use in your story, shoot me a message and I can help you brainstorm.

Death by blood loss.

If stab wounds, severed limbs, and internal bleeding feature in your work of fiction, it is important to consider blood loss. Depending on the location of the injury, bleeding may be quick or rather slow. Blood will clot fairly quickly if the bleeding is slow. A wound to an artery will likely be required to cause death, so make sure that arteries are present in the area your character is stabbed. The average adult human body contains about 5 liters of blood, which is the same as about 8.5 bottles of soda (20 ounce variety), but they will have died and their heart stopped beating long before all of that blood ends up on the floor.

The most common symptoms of blood loss are cold, pale, and clammy skin, racing heart, a tinge of blue in the finger tips, fading vision, and unconsciousness. Unless something else is going on in the body, most of the time they won’t just trail off and die mid-sentence with their eyes open as seen in pretty much every movie out there; they will instead go unconscious.

I’ve worked in two different blood banks and wrote my dissertation on mitochondrial function in human blood cells. I have drawn and processed quite a lot of blood for transfusion and analysis. It wouldn’t surprise me to learn I’ve seen more blood than most surgeons ever will. In case you don’t have this much experience with blood, it will be important to look it up and familiarize yourself with its appearance and properties. For example, the red in blood is due to the hemoglobin in erythrocytes (red blood cells) which are in suspension in circulating blood (about 40-45% of total volume), but when the blood has been allowed to settle (30 minutes to an hour) the greater half of the blood volume will sit on top of the packed red blood cells. This fluid is called plasma (or serum if it has clotted), and it is usually golden or straw-colored in appearance, but this will depend on many factors. Also, unless the victim is somehow injected with anticoagulants, the blood will most likely clot within 30 minutes. Clotted blood has the consistency of Jell-O, especially if it is a fresh clot, and it will shrink and harden over time.

Death by pathogen.

Viruses, bacteria, fungi, and parasites are the most common types of pathogens. There are nearly a million different species of pathogen that can infect mammals, and each of them might have different symptoms and can be deadly, or have no symptoms at all and live symbiotically with their host. Some won’t survive on a surface for more than a second, some can last years. Some can only be transmitted by blood, some by mucus membranes, and some by the fecal oral route (yes, eating poop). Some, like parasites, may have multiple life cycle stages that occur in different animals. They are fascinating to learn about and even more fascinating to use as tools in fiction.

I won’t say much on this subject because it would take an entire book just to cover the basics. I will stress, however, that the most common symptoms presented with these pathogens are not really due to the pathogen, but the result of our own immune systems trying to combat it. Most of these deaths are caused by your own body which kills you in its attempt to kill the invader. Granted, many pathogens will generate and release toxins of their own, or get inside your cells to evade the immune system, or even tinker with your DNA, or commandeer your cell’s own machinery for its own ends. These tiny organisms want to live just as much as we do.

Fever is a common means by which your body tries to eradicate the invaders, but it can fry your nervous system if it gets too high. Your body often tries to repel invaders by producing a lot of mucin in your airway epithelium and goblet cells which is secreted, mixed with water, and comes out as coughs and phlegm of various colors. Mucus can then congest the airway and prevent the lungs from absorbing enough oxygen, resulting in death. Interestingly, the green in pus and mucus is not a result of the bacteria, but myeloperoxidase, an enzyme of neutrophils (a common white blood cell) which converts hydrogen peroxide (also produced by these cells) into hypochlorous acid (bleach) to help kill pathogens.

Death by radiation.

From a nuclear blast, to cosmic rays, radiation can come in many forms and many of them behave differently. Depending on the type of radiation (alpha, beta, gamma, ions, protons, etc.), they will have different effects on the body. Some, like alpha radiation, are so large (a helium nucleus) that they are unable to penetrate skin. Others, like gamma rays, can rip through the body, cutting apart DNA and generating oxidants. When DNA is damaged faster than it can be repaired, the body will shut down and then die over the course of 24 hours to several weeks, depending on exposure. The cells that replicate the fastest in the body will be the first to go, including those that line the mouth, lungs, hair follicles, and gut. Vomiting, nausea, diarrhea, headache, loss of mental faculties, hair-loss and many other symptoms can result in as little as a few hours. The immune system is reliant on the proliferation and function of many immune cells (like lymphocytes and neutrophils), and when they can no longer provide their essential functions, the body will be subject to infections. Cancer can also result from DNA damage to important genes controlling the cell cycle.

There is a common misconception that radiation will contaminate other items, thus allowing it to be spread from one irradiated thing/person to another. This only occurs if the radioactive isotope is what is being spread. There is also a common misconception that taking iodine will help you survive radiation exposure. This only helps if the radioactive element is iodine 131. Taking normal iodine will prevent the harmful radioactive isotope from being taken up by your thyroid. Granted iodine 131 is a common fission byproduct of uranium and plutonium, so having some iodine might be useful in such situations as a reactor breach or nuclear blast.

Before deciding on this mode of death, it is important to look up symptoms for each exposure level as well as the type of radiation that will result from the event.

Take-home message.

There are many ways to kill your characters, so many ways in fact, that you don’t really need to make stuff up. I’ve only listed a few scenarios here, but they are near infinite. Why go in to this kind of detail? Well why not? You can teach your readers something as well as describe something that is visually captivating. That’s a win-win in my book. If you need help figuring out where to start, feel free to contact me.

15 thoughts on “The science of killing your characters

  1. This was a very interesting post. Thanks for sharing it. I must admit, I am a fan of killing off my characters.
    So your radiation one made me pretty sure they got it wrong in Star Trek Into Darkness. Kirk looks perfectly beautiful in that scene where he dies in the reactor. Of course, Kirk looks beautiful all the time, so…

    Liked by 2 people

    • They almost always get it wrong in movies. You could certainly die that quickly from radiation exposure, but the dose has to be really high. It would heat up the body, probably cause blisters, and result in seizures. I also find it laughable that they try to use Khan’s platelets to bring him back to life. Yes platelets are involved in wound healing, but that’s mainly open wounds. They aren’t going to stitch back cells or DNA. Platelets don’t even have DNA of their own, so I doubt anything special was stored in his platelets. Then again, Star Trek has never been praised for its adherence to scientific accuracy.

      Liked by 2 people

  2. Allow me to help with the symptoms of poisonings:

    CNS STIMULANTS (eg strychnine): Over-stimulation of the nervous system leads to tremors, seizures, overheating, and then death.

    CNS DEPRESSANTS (eg opioid overdose): Reduction of heart rate and respiration, loss of consciousness, cooling down, and eventual death due to respiratory arrest.

    ANTICOAGULANTS (eg warfarin): Excessive bleeding. Wounds don’t stop bleeding, blood pools internally, big “bruises” form in the skin.

    PARALYTICS (eg botulinum toxin): Ascending paralysis–that is, starts with the legs and moves upward, until the lungs are paralyzed, death from asphyxiation.

    Um probably most of the rest of the stuff I know isn’t so applicable to humans. Various pesticides work in a lot of different ways. Colechalciferol, for instance, causes metastatic calcification. Metaldehyde causes muscle tremors and overheating. Organophosphates cause classic “SLUDDE” symptoms. But that requires the character deciding to use pesticides.

    On the subject of bleeding to death, I can comment on that as well. The separation of erythrocytes and plasma is kind of an artificial thing you only tend to see in lab tubes. Blood pools out a lot like you’d expect, and clots in the deeper areas of the puddle. The clots are, as you say, surprisingly like jell-o, maybe a BIT firmer (if you opened up the body, you’d find these clots in the aorta/vena cava and inside the heart chambers, too). Depending on where the injury is, there might be blood coming up into the mouth from the lungs. Takes about 30 seconds to bleed to death from a major severed artery. There’s likely to be agonal gasps. Big pools of blood inside the body aren’t likely to clot for quite a while, if at all (eg if they bled out internally). A ruptured spleen, liver, or kidney has the potential to bleed out internally the same way you would if you got your throat cut.

    One thing movies ALWAYS get wrong, which is kind of funny, is that the pupils NEVER dilate. Obviously because the actors aren’t actually dead. But it makes me lol. I suppose they could use CG to do it, though.

    Liked by 2 people

    • Glad to know I’m not the only one who finds it interesting. Thanks for all the additional info. I think Hollywood should hire us as consultants… except they’d get frustrated with us pretty fast. Nobody likes to hear that everything they are doing is wrong.

      Liked by 2 people

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  4. Brilliant post. I managed to get you into my blog post today, and thought it ridiculous that I haven’t taken the time to write a comment. So here’s a rather long and rambling question for you.

    A concept I am using in my current WIP is to have people who were exposed to radiation passing mutations down to their children. These people were basically kicked out of all the remaining settlements shortly after the nuclear apocalypse. They are treated as lepers because of the misconception that they carry radiation and will infect you with it (like you mentioned in your post).

    Due to their isolation from settlements, they grouped together into small clusters and some have became rather feral. This also led to inbreeding—there aren’t a lot of options for these people to procreate. Now you have a generation of people with varying levels of physical and mental issues. It’s sort of a Hills Have Eyes type deal. However—and this is where I’ve ruined everything scientifically—some of them have developed glowing green eyes (this is one way “normal” humans can identify and kill them for bounties…people are jerks in my world). There are also rumors some might have developed supernatural abilities.

    So I know I’m basically kaput scientifically with the idea of supernatural abilities, but could glowing green eyes be explained away with science? Is there a even a remote possibility? There’s also the idea I see played on of people only being able to use a certain percentage of their brains (I’m thinking of the movie Lucy or Limitless). Could some sort of genetic mutation allow for someone to access more. Or is the very concept of “unlocking your brain” nonsensical?

    These are the questions I ask myself as I wait to do rewrites. Some of it I will likely file away in the, “Just press the believe button,” file. But if I can manage to even blend an iota of science into it, that would be stellar. It’s worth noting I have some completely outlandish weird-science going on outside of this, but the more concepts I can ground in quasi-reality the better.

    Liked by 1 person

    • Hey QE,
      Thanks for spotlighting my blog today!
      As for your question, you can definitely explain glowing green eyes, it just depends on how much background you are willing to delve into. I don’t think you need to explain everything. The only readers who really care about such things read hard sci-fi, but soft sci-fi readers will likely be disappointed if there aren’t any supernatural powers or strange mutations. But if you want to explain at least a few of these things, there are plenty of ways to do it. First off, do the eyes glow in the dark (i.e. emit their own light?) or do they fluoresce when exposed to another type of light (e.g. UV)? Fluorescence is easier since there are a number of natural compounds, even in our own bodies, that fluoresce when exposed to UV, and a mutation might feasibly result in an accumulation in the iris or cornea (e.g. flavins, retinol), or mutations could cause already existing proteins like melanin, to fluoresce more than they usually do. This might require “normal” humans to carry around a UV light. As for glow in the dark or bio- chemi- or phospho-luminescence, this is a bit trickier. For phospho-luminescence, glow in the dark materials, certain compounds like Strontium aluminate may have had to accumulate in the eyes in some manner. Bio- and Chemi- luminescence exist in many living systems, but they have dedicated enzymes and proteins responsible for producing the green light (e.g. Luciferase and luciferin in fireflies). We use these a lot in genetic studies in mammals by inserting these genes and tracking gene expression by the amount of emitted light, but no mutation caused by radiation would accidentally result in this. If you want, you could have had some scientist insert these genes (behind an eye specific promoter) in this line of humans to keep track of who was exposed to the radiation. I think this is the most likely of all the possibilities and would only require a footnote in the history of the people following the radiation exposure.
      Radiation could cause a lot of germ-line mutations and deformities, cancers, and all kinds of peculiarities that might look supernatural, but as far as things like telekinesis, telepathy, and other things, I don’t thing so. If you want people who are ridiculously strong, you can have mutations develop in the myostatin gene which prevents muscle growth. This type of mutation exists today in humans, but it is rare, and muscle growth is pretty remarkable. They even mutated this gene in bulls to produce more meat (Belgian Blue bulls). I once worked with some mice with this mutation and they were pretty bulky. If you send me a list of the types of physical changes, I may be able to narrow down some gene targets, otherwise you will probably have to put it in the “just press the believe button” file. I don’t believe there is any evidence of accessing more of your mind leading to any supernatural abilities. If anything, it might just improve your memory recall, speed, smarts, etc. The thing is, we do use all of our brain, not 10%, it is just that we don’t use it all at any one time (I imagine that would result in a seizure).

      Hope this helps,


      Liked by 1 person

      • Thank you so much for this amazing information! You’ve certainly given me a lot to think about. The information about the myostatin gene is golden.

        One of my friends/clients attends conventions to promote his book and talks about having to answer questions about the book. Having intelligent answers, instead of saying “because I thought it sounded neat and it’s a great visual,” is important to me. So even if this doesn’t manage to find a way into this particular book, at least I will have something more intuitive to say. I’ll be copy and pasting this into my world building notes. As this is book one in a large series, I’ll likely have more opportunities to introduce doctor/scientist characters in the future to address some of the nuts and bolts of the world.

        Thanks again for taking the time to write this and for offering so many different options to think about.

        Liked by 1 person

  5. Hello,

    I found your site because of the link that was provided on the Quintessential Editor blog. I love the science and thought that you use to better describe this topic to a knucklehead like myself. As an aside, I have been flying airplanes for over twenty-five years in civilian, military and commercial aviation backgrounds. If you ever have any questions about airplanes for your works, please ask.

    With your permission, I would like to become a follower.


    Liked by 1 person

    • Hey Rob,
      Glad you enjoyed the post. I may definitely pic your brain in the future about airplanes. Do you, by any chance, know much about seaplanes? No worries if not, I just have a scene in my current work in progress where I could use some advice. If you are interested, I might ask you to write a guest post debunking common aviation myths and how to portray flight scenes. I look forward to chatting with you in the future.
      Let me know if I can be of help to you in any way.



      • Phillip,

        Please ask me anything you want to know about airplanes. I have never flown a seaplane, but I know many people who have. I might have some questions about medicine or science in the future too.

        As far as a guest post, I would be honored.


        Liked by 1 person

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