My story takes place in medieval times, where ghosts are a common sight. I'm not gonna go in too much detail, but lets just say that it's perfectly normal for living human beings to interact with ghosts, even in broad daylight.

Unfortunately, some of the ghostly members of society can be very troublesome, especially because of some common ghost abilities they possess (hehe), the big five being:

  • Intangibility - kinda hard to physically hit or catch them
  • Invisibility - hard to find them if they don't want to be found
  • Possession and Shape Shifting - risky to "test"/kill someone suspected of being a criminal ghost: is the person a shape shifted ghost or someone who is actually possessed by a ghost?
  • Levitation - doesn't make it any easier to hit or catch them either

Since this takes place in medieval times, Ghostbusters-type technology and gadgets are out of the question, and I also want to avoid "blessed" weapons, because not all ghosts are pure evil after all. The ghosts also can't harm each other, so you can't just enlist some friendly ghosts to take care of the troublemakers.

I want the heroes of my story to use some kind of material for their weapons that would make sense to be effective against ghosts, either scientifically (if you assume something like ghosts can exist) or... mythologically? This material has to be availalbe in medieval times.

Ideas I had:

  • Mirror swords: plays on the "ghost in the mirror" trope by using it against ghosts. If you manage to hit a ghost with a mirror sword, they're gonna be trapped inside the sword. Not sure how readily available mirrors were in medieval times.
  • Ghosts might have an aversion to a material that is commonly used in burials - it reminds them of their own death after all. Not a big fan of this idea, as I want something that works for all ghosts universally. A ghost who never had a proper burial wouldn't be affected by this material.
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    $\begingroup$ Ok, this may sound like a cop out answer but... make something up yourself! You are the author, you have created the concept of these ghosts, which means that you come up with what they are vulnerable against. Since ghosts are fiction, and there is no ISO 31415-9:2017 Standard on Fictional Incorporeal Beings, you have complete freedom to make up these ghosts' strengths and vulnerabilities as you see fit. There are no rights or wrongs here (beyond making up your own rules for these ghosts and then later on breaking them). $\endgroup$ – MichaelK Sep 27 '17 at 10:53
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    $\begingroup$ I agree with @MichaelK . Your question basically reads: "By my own rules, these beings can't be caught or killed since they have no vulnerability. What are they vulnerable to?" $\endgroup$ – Guran Sep 27 '17 at 11:01
  • $\begingroup$ Anyone's The Screaming Staircase by Jonathan Stroud? It's pretty similar to the question asked $\endgroup$ – Manav Sep 27 '17 at 11:12
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    $\begingroup$ worldbuilding.meta.stackexchange.com/questions/4317/… Furthermore I don't think there is enough info to employ worldbuilding techniques here. All we got is "ghosts are real and OP, halp" nothing on how they work, how are made, what mysticism or theology they are based on, nothing actually useful. $\endgroup$ – M i ech Sep 27 '17 at 12:39
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    $\begingroup$ @MichaelK In this case totally justified. $\endgroup$ – Ash Sep 27 '17 at 12:57

Among the materials considered to repel or block ghosts (no literature reference on these, of course):

  • iron, usually in the form of spikes
  • flowing water
  • paper or straw (used in Japanese mythology to seal passages with the other world)

To build a trap you would need a bait to lure the ghost into a suitable trap. Again, ghosts seems to be attracted by living substances, such as blood or sperm (that's why in some cultures seeds are stored under the bed, to catch the energy released during the intercourse and prevent it to be harvested by less benevolent things).

Your Ghostbusters can make a cage with the above materials, put some bait in it and wait for the ghost to enter it.

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    $\begingroup$ Good to see an answer based on traditional materials. Plus one. $\endgroup$ – a4android Sep 27 '17 at 13:03

If your ghosts are made via necromancy or an 'unpure' process then silver is a pretty good bet, as it was considered to be a 'pure' metal (and thus anathema to undead or demonic forces). This doesn't necessarily care about whether the ghosts are good or evil.

From a pseudoscientific viewpoint you could consider ghosts to be exotic waveforms, of a sort, and anything that puts out a suitable cancelling signal or resonates with the ghost until it tears itself apart might be handy, so a variety of crystals (perhaps even a circle of salt, in a pinch) could help trap or even outright destroy your phantoms.

  • $\begingroup$ Let me point out here that waves are never "cancelled out". They may be superimposed on another wave but once the waves divirge from eachother they are just as potent as before. You can only ever create a very localized zone where a wave is nullified by a counter-wave. $\endgroup$ – MichaelK Sep 27 '17 at 11:07
  • $\begingroup$ @MichaelK: you realise we're discussing ghosts here, right? $\endgroup$ – Joe Bloggs Sep 27 '17 at 11:30
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    $\begingroup$ Yeah. And? You brought up the concept of waves and cancelling out waves. Just wanted to point out that even in reality this is not something we actually do. $\endgroup$ – MichaelK Sep 27 '17 at 11:41
  • $\begingroup$ @MichaelK Fair point. Pseudoscience doesn't exactly lend itself well to real physical concepts, $\endgroup$ – Joe Bloggs Sep 27 '17 at 14:37
  • $\begingroup$ Can you give reference why you/people think "silver is 'pure'" ? $\endgroup$ – Vylix Sep 27 '17 at 17:13

It's not about the material but the process to acquire it. Ghost are spirits, essence of a person (or animal?).

So what would interact with them must also be an essence of something. So the first way to get it would be alcheming the source in great quantity to leave pure core.
The second one would require to find the real "source". So no gathering nuggets or screening. You would need to mine the vein and get only iron or gold without any contamination.

Also the easiest way would be to use spirit to kill spirit. So you would need to get the spirit of alcohol and then mix it with ghost and set it on fire. Of course alcohol is a vapour so the bottles used to fight ghost would have "best before" date. And that how you make money selling those potion bottles.


Iron was once considered a way to repel or harm malevolent supernatural beings. See here and here. So an iron sword, or iron anything really, could be useful.

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    $\begingroup$ Hit the possessed person over the head with a cast iron frying pan. $\endgroup$ – pojo-guy Sep 28 '17 at 2:29
  • $\begingroup$ @pojo-guy exactly! $\endgroup$ – Styxal Oct 3 '17 at 14:57

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