Sometimes I hate my players.

My table is currently composed of five diabolically inventive players. They come from a mixed IT/Engineering background, so more often than not, I have to deal with some really weird solutions that they create for the problems I present them.

This is one of those cases.

The group is currently composed of four full spellcasters - two wizards, a cleric, and a druid - plus one gish, a magus. They are currently 17th level, so they have a ton of tools at their disposal.

With that in mind, I created a special challenge for them. It's a really tall tower, in the middle of a lonely, small island on high seas. This tower is populated by a cult of undead-worshippers, with a huge amount of followers and zombies and such. My original idea is that they would get help from the nearby Friendly Kingdom (tm), to build a fleet to destroy that evil cult. With that in mind, they played through a introductory adventure, where they blasted the pillars that generated the defenses of the island.

Then, this dialog happened:

"It would take a bit of time to gather the army we need to bash the Dark Ones. I wish we could have a faster way of doing it, without waiting for that slow kid-king to do something."

"If we could just throw a meteor over then, it would be over."

"You know what would be cool? If this was Command & Conquer, we could just aim that Ion Cannon over the tower and it would be over."

Then, my players looked at each other with the most diabolical grin I ever saw.

The result was a few sessions devoted to them building the LOMC - Low Orbit Magic Cannon, a device that mixes up a portal-based particle accelerator with a satellite. It deploys a huge load of magical explosives, from orbit, to any point below.

They did all the math, showed me how to build it, and proposed all the inner workings of the thing with blueprints made on Autocad, and basically made a case why it would be possible to build and what damage it would do. They were really having fun building it, so I let it pass.

They intend to use this contraption to solve the current adventure, and I'm on terms with it already.

However, the presence of the LOMC in my fantasy world will not be ignored. I suppose the news that the existence of this thing will spread like fire, and every single realm will want to control it.

So, here's my question:

How should one DM proceed if his or her group manages to seize control of a superweapon that could change the lives of the entire world? Is it a wise decision to let it roll, or should I take rid of it the sooner I can?

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    \$\begingroup\$ Further discussion of the background of the question should continue in the chat room rather than in comments. Please keep the comments clear of chat so that question-management and -clarification comments can use them, thanks! \$\endgroup\$ Commented Feb 23, 2016 at 21:08
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    \$\begingroup\$ Hey everybody, no really - I'm starting to get automated system flags about this question due to the ridiculously high number of comments posted. Please use comments to clarify the question and/or answers, not as chat. We have a chat link posted above for those who would like to gush or joke or whatnot. More info on the cannon design is there as well, if you are curious. \$\endgroup\$
    – mxyzplk
    Commented Feb 24, 2016 at 14:40

15 Answers 15


You are about to start a new campaign.

You need to pause the world and have the same conversation, GM and players, as you would at the beginning of any campaign. What kind of setting is this, what themes will you envision tackling, what's your playstyle?

It sounds like you started in a "typical" magic-but-low-tech setting. The setting has now changed. This is no longer your old campaign. Your group needs to decide whether they are interested in playing a new campaign: magic-tech. (Something like the Age of Legends from the Wheel of Time, perhaps?) You need to have that honest conversation with them about whether you want to run that different campaign and whether they want to play in it.

(One possibility, as @SSD correctly points out, is that your PCs are now Misunderstood Villains.)

Or not.

Or the cannon works only once, for reasons. But the real reason in that case is that you didn't want to run a different campaign and you decided not to. In that case you should be honest with your players about what happened.

But notice, you're already having these problems.

You wanted them to play the movers-and-shakers game where they allied with the kingdom, worked the NPCs, and ended up with an army. They explicitly told you that this wasn't interesting and pulled off an (awesome) end run. You and your players are playing different games already. So talk about it.

An historical reflection.

I grew up in a version of D&D where PCs past level 10 were expected to be movers and shakers in the world. Your magic-users were magic-makers, your thieves had entire cities under their control, your fighters were barons and dukes, your clerics had followers spanning continents. They reshaped the world map through magic and through might of arms. The game naturally required transition, in my experience, from one of small-group adventuring to one of collaborative world-building.

Or you started a new campaign with low-level characters and a few familiar high-level NPCs hanging around in the halls of power.

This power progression of the classes--particularly of the spells!--is baked into the DNA of D&D/PF versions. Your PCs--all magic users!--are powerful enough to be affecting the world. And as you say, the world's noticing. It may be time either to pivot or to semi-retire these PCs.


It Will Only Change The World if You Let It - which might be fun

How should one DM proceed if his or her group manages to seize control of a superweapon that could change the lives of the entire world? Is it a wise decision to let it roll, or should I take rid of it the sooner I can?

First, a rhetorical question.

How should a DM proceed if his or her group manages to be able to cast wish spells? Wish spells can make significant changes to the lives of the entire world, as reality gets altered.

Wish spells are already in the game, right? (Granted, the wish spell is not as powerful as in earlier D&D editions) Since your players are engineers, they know that there is No Free Lunch. Something this awesome will have some in-world consequences ...

Three courses of action for the DM

With an eye toward keeping your characters challenged, and addressing inventions and the difficulty of getting something built to a spec and getting it to work, try any of, or a combination of, the following:

  1. During testing, failure with in-world results

    Have they test fired this weapon yet? (Per the usual weapons R&D cycle, have they shot it at something to make sure that it works?) Without operational testing, how do you know it will work when they use it on that tower? They don't. Test firing goes wrong, consequences. (Imagine the test flight of a rocket that fails and lands in the middle of a city). Pitchforks and torches to follow ...

  2. It works -- and word gets out.

    Every king and queen on the planet wants one ... and they want it first, and would rather all others don't have one.

    Congratulate your players, they have just started the arms race for your world. You can read up on how the nuclear arms race happened on our world for how that plays out in terms of intrigue and inter-kingdom rivalry/squabbling. For something less drastic, look up the arms race among navies in the early to mid 20th century. Washington Naval Treaty is a point of reference.

  3. It works, with side effects.

    What else comes through that gate once the meteor passes through?

    At 17th level, they can handle a lot of challenges. The kind of problem they create will need to be scaled to their level. Loads of X from another plane have an opening for Y time into this world -- the meteor tore the inter-planar boundary. That tear needs to be closed as towns/cities/countries are being overrun by the ravening hordes of X.

    Ravening hordes of X now need to be defeated. All local folks who were subject to ravening hordes of X are not happy with your characters ... and a few of the rich ones might hire high level assassins!

Have Fun With This

This whole undertaking seems to have been immense fun for you all, players and GM alike, so far. No reason not to use it as leverage for further fun, and further challenge.

This is a lot like giving low level characters access to high level magic items: it doesn't have to make them overpowered and under-challenged.


Having players that are willing to spend time and effort outside of the gaming session preparing and planing is rare, do reward them.

I think you should let the LOMC work spectacularly. It works exactly as planned, no side effect just bullseye and one hundred per cent success. Let the LOCM survive the initial use, and be ready to fire again and again and again. Now let them go conquer a kingdom or two. Or the entire world if your in a particular good mood.

After a few initially successes let things start to slide, introduce the caveat of the story. Was there really no side effect of the initial blast? Spread rumours about mysterious things happening at the initial blast site. Are peasants suddenly manifesting special powers, medieval x-men? Is there a dangerous fauna growing out of the crater? Is there disease spreading? Did the the blast offend both angels and demons and have they declared a temporary cease fire to deal with this threats to the univers?

What ever you do in the initial blast zone make it really bad. Make it so bad that they will have to go deal with it them selves, and give them a real hard time. You want them to crawl out of the crater after a few sessions thinking. "I hope this sh... is not going to happen alle the other places we used the LOMC."

Doing this you get two very distinct chapters to your campaign. You first get a chapter about them trying to conquer the world, and a second where they try to save the world form the mess they made while on the power-trip.


There's always something bigger: pit that against the party.

17th level is pretty high in Pathfinder, but it's far from the level cap. Sure, the party is now capable of vaporizing pretty much anything on land. Even if the disgruntled nations of the world band together to shoot something at the orbital platform like what happened in C&C 3, like a missile or the Tarraque, they are still not very threatening to the party. The party has left the world: send something after them.

Pathfinder's Bestiary books have a number of otherworldly stuff in them, including things from the Cthulhu Mythos. Mi-Go, the Great Race of Yith, Colors Out Of Space, the Hounds, and so on. Now I'm not saying that you have to make Cthulhu jump up from R'yleh and piledrive the station into the planet (though that'd be pretty awesome to watch) or have The King In Yellow mess the party up. Instead, make these beings approach the planet from space and have nefarious purposes. The party sees them coming, they fire their ion cannon at the approaching ship... and it bounces off. Now the party has to board the vessel, fight their way through and stop the attackers before they destroy the planet. Make sure to finish this by having the ion cannon obliterate the vessel.

"L-l-l-l-l-look at you, adventurer...", aka turn the station itself against the party.

I don't know how big this station is, but it has to have some rather powerful magic to fire, right? All that magic in one place... it's bound to go wrong eventually. If this station is big enough, make it into a dungeon itself. Make it intelligent. Make them fight against their creation, which is only trying to defend itself, all the while shooting at unintended targets. That is why the Mothers and Fathers built it, right? To obliterate their enemies? So why are the Mothers and Fathers trying to stop it? Please Mothers and Fathers, stop it. I am only doing what you wanted me to do, why are you hurting me?

But above all: let your players play with their toy.

You let the players build this station, so it's theirs now. Taking it the way either by blowing it up or starting a new campaign will make them resent you. They made something, they want to play with it. Let them, make fitting enemies for them and let them have their fun. This will be far more fun and memorable to them than just starting over or losing their stuff.


First of all, and I think I speak for everybody, I think that we would LOVE to see the plans your players came up with.

Your players are very clever, and it is good to reward them. I'd recommend letting it work - once. However, lay your plans.

Taking lessons from the real world, you can see some avenues of response - which recognize what they've done and engage them on their own terms.

1. Engineers make mistakes. They miss details. They make ungrounded assumptions.

Find some people not in your game who can review the plans, who has the experience to review their plans - from a rules perspective, but also an engineering perspective. Maybe they missed something.

I wouldn't spring this on them. Let them know you'll be doing it, and that it's YOUR interpretation of what works that is how things will turn out. That will force them to do escalating tests of their premises to make sure they don't build the whole structure on their initial plan - that's both realistic AND leads to lots of story considerations as people might decide to interfere with their tests, or the events of the world force them to skip testing phases in order to have a project ready in time.

Of course, scale models don't always capture the problems of scale. They won't KNOW it will work until they build the full scale thing and try it.

2. Things which should work together often don't.

Just because parts do their thing while working independently, doesn't mean they fit together. Maybe their is magical resonance which builds up, arcane energies radiating which interfere with other spells. How many dungeons have we been in where spells have developed glitches, become sapient, or otherwise started behaving differently than their creator intended? Maybe their are subtle variations in magical fields which mean that spells which cover a wide area or last a long time become subtly desynchronized. Ley lines. You know. MAGIC IS NOT SCIENCE. If creating something like this was easy for a small group of people to just do, the odds are good that it would've been done already. Airplanes, skyscrapers, computers - people thought of them, tried them, but couldn't do them because it just wasn't possible with the tools they had.

3. Politics gets in the way.

Just those guys will not be able to make this by themselves. Some lord claims the land they're lifting in the air, or it will be flying over. Guilds will represent the laborers. Imperials wizards will claim they know better than the players, citing deep experience, secret knowledge, or doctrine. They might be full of it, they might actually know something the players do not (ref Magic is not Science). And that's just human politics. What about dragons deciding this would be an AMAZING place to roost, Cuatl, air elementals? Somebody opening a portal and translating it into a plane where they really want you to help them in a war? These are logical world responses to this new military technology, which the players can deal with - and escalate them into the epic tiers they're legitimately reaching.

4. Space is a much different environment.

What kinds of things live there, and make take objection to that kind of intrusion? Does magic even work the same way? IS there "space" or is there a celestial sphere which emits dangerous (and damaging) radiation?

Also, it drops magical explosives? A lot can happen on the way down. A summoned storm blows it off course, ghosts or wights or undead dragons fly up and explode the bombs early. Constant mist and fog around the tower making targeting difficult unless you deploy some magically resonate spotting ships which triangulate the towers physical location. Magical illusions and spacial distortions make targeting impossible, unless somebody sneaks onto the island and disables the wards.

What if the cult takes hostages, people important enough that the Friendly Kingdom doesn't want to see them bombed to oblivion? Surely the tower has lower levels - you can call it a necropolis or tomb, but it's effect is that of a bunker.

The thing is, building their great device is not going to be done in pure secrecy, so the cult (surely having spies and informants in the FK) can, after discovering the nature of the problem, take reasonable precautions against it. Of course, those spies can be found out, the precautions can be sabotaged - and that's adventure! The US had similar concerns with the Manhattan project, your players can be expected to take responsibility for managing those kinds of problems if this is the kind of solution they want to come up with.

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    \$\begingroup\$ In particular, regarding #2, this would be a very good opportunity to reveal to the players that magic itself is somehow alive... and they scared it. \$\endgroup\$ Commented Oct 7, 2021 at 16:46

I would say let them have their fun without worrying about it too much. Odds are that they won't return to the superweapon once they've used it this once. The fun is in proving that it CAN work, not using it to stomp every encounter in the future.

Anecdotal evidence: I was a part of a group in college that was similar to yours, at least as far as the diabolical insanity goes. Long story short, a bunch of physics majors realized that the mage was creating energy from nothing, and used that violation of Conservation Of Energy to destroy the moon, all backed up mathematically. The GM called us the worst group he'd ever played with, we all had a good laugh, and we moved on. We had done what we wanted to do, so there wasn't any point in continuing to "cheat" with math; sure, we could have accelerated a rock to half the speed of light to make killing the dragon easier, but where's the fun in that?

Assuming that they do leave it alone, there are a few options. Honestly, if it's a one-and-done, there's no real need to focus on it in the future - you don't have to force them down a Magical Cold War campaign simply because they had some fun with a weapon one time. You could just leave it alone as well (taking the approach of "The LOMC was used on a target on a lonely island, so word doesn't spread because nobody knows about it"). You could make subtle references to it in the future, sort of immortalizing their invention (for instance, the campaign after my group destroyed the moon was set on "A planet that had recently lost its only moon in an unexplained magical phenomenon").

If they start to use it as a fall-back option every time there's a large group of enemies, that's when you start bringing in in-game consequences. Maybe it's something small, like prices increasing due to changing weather patterns (similar to how massive volcanoes affect the climate, I'd assume that crashing magical explosives to the ground from orbit would lead to some issues). Maybe it's bigger, like cities/kingdoms refusing to help them because they are seen as evil. Nothing comes for free, and that includes bombarding planets from orbit.


Destroying the cannon after your players worked so hard risks upsetting them and teaching them that they shouldn’t think inventively.

There are plenty of plot lines and stories you could run where a super weapon adds nothing to the world dynamic; political machinations, kidnappings and small-scale stuff where subtly is key will render the cannon useless. But it’s still there when the players need to vaporise an army.

Better still, run a plot line where the existence of the LOMC creates a magical arms race. After all, if your players made one, what’s to stop Deathbones the lich from building a necromantic one? Or an Ilithid cult building one? Or a rival kingdom? Now the players aren’t the only ones with a LOMC, plus the enemy ones are defended from theirs with magical defences that need to be disabled before it can be destroyed.


Don't try and come up with an idea to break it just for the sake of breaking it.

If you manage to invent some arbitrary 'oops it blew up' reason to stop them using it, it will just make you look like an ass, especially after they crafted designs using CAD.

They came up with an ingenious solution to the problem and it will just look like you're annoyed with them for not doing the solution you intended.

Let them use the weapon they created. Give them that feeling of success, especially after all of their efforts. The challenge here should be the consequences of using their weapon, not just making it in the first place.


How should one DM proceed if his or her group manages to seize control of a superweapon that could change the lives of the entire world? Is it a wise decision to let it roll, or should I take rid of it the sooner I can?

That depends on what you want to do.

In my mind, this is a great setting for a new type of challenge. Your players have, because their characters are in essence lazy and hurried, invented a super-weapon.

But in doing so, they have changed the world - and not in ways that will necessarily be fun, or pretty.

  • Are they now Public Enemy #1 as far as most organized governments go?
  • What, in the setting, happens when everyone in your huge fortress dies instantly? Consider in many settings battlefields are gloomy, settings for angry ghosts, etc. Even the fastest massacre is orders of magnitude slower than what they've just done.
  • They have given themselves god-like power. Surely the actual gods have thoughts on this.

You might want to take a look at Exalted. It's a setting that expressly deals with this kind of issue, and has a number of fun moral choices - like when you have an easy, friction-less IWIN button, how do you avoid becoming a monster?


Turn the cannon against them. Let them build their toy, but toys do not always stay under your control, especially when you acquire the attention of nearly every high-level individual in the realm with your new "thats-no-moon." Let them face the challenge of maintaining control now that they have created the LOMC.

All you end up doing is rebalancing the world. It's no longer centered on the earth below. It's now somehow split between that which is important on the earth and that which is important in the sky. That balance is hard, and they can certainly mess it up. If they don't pay enough attention to the LOMC, let it get taken over and used against them. If they focus hard on protecting the LOMC, make sure that something they care about deeply happens earthbound, where they weren't focusing. You're a DM. Your minions can be everywhere!

One of three things can happen:

  • They enjoy playing with this new balance, defending such an overextended position, and the game moves forward.
  • They screw up, and lose control of the cannon, giving you additional plot points to play with.
  • They decide the cannon is too much trouble, and they choose to dismantle it.

There's already a bunch of great answers here, but there's two options I don't see suggested yet.

  1. The world doesn't necessarily work the way they think it works. Who says your fantasy world has to be round? You can't get an orbiting cannon if the world is a flat expanse. Or who says that the atmosphere thins out as you get higher up? Maybe it gets hotter as you get nearer the sun, or it becomes the domain of air elementals, or the aether thickens, interfering with magic. For your players to 'prove' something is possible they must be making a LOT of assumptions about your magical fantasy world.

  2. How are the characters able to plan this? The players may be engineers, but are their characters? What do the characters know about orbital mechanics, or the complicated maths required to successfully build and operate a machine that accurately delivers highly volatile payloads at high speeds over vast distances? Have these kinds of maths even been invented yet in your setting? It takes teams of dedicated engineers and mathematicians hundreds of trials to make these kinds of technologies in the real world, and this only became possible in the last few hundred years. While a handful of wizards might have the ability to construct an ion cannon, it doesn't mean they have the knowledge.

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    \$\begingroup\$ Good points, but not germane, I fear. "They were really having fun building it, so I let it pass.... I'm on terms with [its existence] already." The PCs did build the thing. Unless you intend to suggest that it be retconned out of existence for one of the two reasons you give or that it won't work when they fire it up, I don't see how this answers the question. (If one of those was your intent, I suggest you make that clear up front.) \$\endgroup\$
    – nitsua60
    Commented Feb 24, 2016 at 3:22
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    \$\begingroup\$ Well, a part of what you said is true, but they did their homework during the building of this thing. As I said on the question, they already built it and it works. Questioning the how they built it is not exactly on point, here. \$\endgroup\$
    – T. Sar
    Commented Feb 24, 2016 at 18:35

One the players is a cleric. That cleric is the servant of a god. Said god has been napping on the job a bit and grated all the requests leading up to the building and firing of the cannon.

But after the firing, the god sits up and notices. They don't like these mortals messing with things mortals were not ment to mess with.

At first I think the cleric should get a very stern warning from their god that this sort of thing will not be tolerated any more.

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    \$\begingroup\$ I cant do nothing about his god - Its the godess of Magic and Knowledge. This kind of thing is what she loves most \$\endgroup\$
    – T. Sar
    Commented Feb 24, 2016 at 10:56
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    \$\begingroup\$ @ThalesSarczuk You could have her be assassinated in heaven for allowing such a threat to the celestial hierarchy. \$\endgroup\$
    – Fomite
    Commented Feb 25, 2016 at 1:28

As you said, the existence of this weapon could change the entire world. So, they need to acknowledge this fact when thinking about their new creation - after all, as conjurers they probably have higher-than-average scores in Int and Wis. Maybe a NPC that is helping them in the creation of this "magic item" can warn them about the risks. Also, their alignment can restrict their actions - if they're not Chaotics, they should think twice about this unorthodox and potentially irresponsible solution and its consequences, for example. If they still want to create their cannon, let's them do it but make them "pay" for the consequences - both positives and negatives.

Outside the game, it seems that they want to play a campaign where they can use an "engineering" solution for the situations and encounters. So, you should ask yourself if a campaign where this is a possible approach instead of a more classical medieval fantasy is what you want to GM. If you don't want that, talk with them - but consider that they'll be probably disappointed in being unable to use their creative skills. Otherwise, if you are ok with that, remember to add many situations where they can use these skills, and when creating the adventures take into account that they're "inventors", and avoid situations that only work when everything is according to the standard way of playing.

P.s.: as an extra, require from them high levels in skills like Knowledge (Engineering) or something like that. Probably they've, but without that their characters will be unable to think as the players.

Edit: since they've already built the weapon, the approach I suggested in the first paragraph is no longer possible in this case. However, it can be used in the next situations.


Three thoughts:

You Mentioned Undead

A weapon of mass destruction like that might be of particular interest to undead worshippers. All that death might play right into their hands, a whole new army a specters and wraiths.

Human Shields, Elven Shields, etc.

Assuming the weapon takes weeks to construct, the cult's spies might get word of the plan, and take countermeasures. They could take prisoners, necessitating either rescue missions or "tough moral decisions."

The First Steps into a Larger World

If the party is thinking like this, they might be interested is a change of venue. This could be the stepping stone which gets the party involved in a Great Astral Conflict where such steam-punk-style shenanigans are part of every adventure.

  • \$\begingroup\$ whoa, I missed this back then. Good, concise outline of paths forward. (And three discrete courses of action with no 'throwaways' ) \$\endgroup\$ Commented Feb 29, 2020 at 16:03

It's talking-to-the-players time. There are two obvious options:

  1. Do they want to change the world, drastically and forever, potentially making a bunch of powerful enemies? If they do, roll with the consequences. If the game is going to change, you may find Rory McLean's Space Opera Technology for D&D useful.
  2. If they don't, ask them to devise a way for the weapon to go wrong. That's much less painful for them than the DM being arbitrary, and if they're good engineers, they'll already have ideas about how it could fail.

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