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How can I, using existing spells in D&D 5e, create a Surveillance System?

This Surveillance System should do the following:

  • Be able to see what happens in different locations at the same time.

  • Be able to show what's being seen in something like a screen.

Resources available are:

  • Some preparation (like invoking some kind of creatures or placing spells or magical items in some locations).

  • Virtually unlimited money/spellcaster time.

Criterion is:

  • minimizing cost to surveil a location 24/7.

Any of these costs should be explained (e.g.: one L3 wizard per location surveilled.)

I'd like to keep it within existing spells, not needing to create some new spells, though it doesn't need to be strictly RAW.


I will explain here the context for which I'll use this Surveillance System, though it should be used for other contexts that require the same criterion.

There should be a huge resort where the richest nobleman go to satisfy their most cruel desires. There, dungeons and arenas are set where kidnapped adventurers find their fate, which usualy is a cruel death. But this kind of amenity sometimes requires the gladiators/adventurers/players to be inside a dungeon, and there's where our Surveillance System is needed.

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    \$\begingroup\$ This is a very broad question, I think. \$\endgroup\$ – Erik Nov 22 '16 at 12:12
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    \$\begingroup\$ @Erik but just narrow enough to not be too broad imho. \$\endgroup\$ – Trish Nov 22 '16 at 13:13
  • \$\begingroup\$ Hi Albert--I made some small changes to the question; from the posts that have come in I think it's clear that the answer to your question "can I make...?" is a trivial "yes." This way I hope it still gets at your desire, but in a way that helps voters know what distinguishes a good from a bad answer. \$\endgroup\$ – nitsua60 Nov 22 '16 at 14:37
  • \$\begingroup\$ Can the system use Magic Items? \$\endgroup\$ – enkryptor Nov 22 '16 at 16:46
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    \$\begingroup\$ It would be very helpful to have a context for why you want this information. For example, if you are a DM designing an area or a player planning on setting up surveillance, it's a very different situation. Given some hints within your questions, I am guessing you are a DM setting up an area and you want to come up with a way to set up magical surveillance that stays within the rules as closely as possible? \$\endgroup\$ – Calvin Smith Nov 22 '16 at 17:05
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How about the impy route? Hire Imp-surveillance Incorporated today and get 100 imp surveillance post for the price of 99!

We provide a lvl 9 caster and demand our employer to be a corrupt state with death sentence. Our work process is as following:

  1. Of course, we need spell components, so someone needs to get sentenced to death. The blood of that poor guy gets collected for magic purposes.
  2. Our caster uses the lvl 3 spell "summon lesser demon" (from Unearthed arcana), or rather a fiend/imp specific variant of it, to call a few dozen imps while standing in the protective circle in an otherwise enclosed room.
  3. Our wizard keeps up the concentration for 1 hour while casting Planar Binding (5E PHB p 265) in a 9th lvl slot to bind the imps for a year. This consumes a 1000 GP gemstone per imp, but that is a bargain for one year of nonstop surveillance!
  4. Finally, the bound imps are ordered to monitor a place each and to call in for somebody to check the place once something specific happens, like people gathering with torches to try to torch the parliament or the presence of an outlaw Paladin.
    • The basic package's method for calling someone includes running around, yelling for backup and recording things for later usage of authorities in the shape of pictures and scribbled notes.
    • The premium upgrade method for just an extra 9009 gp/imp involves a sending stone (PHB p 255) for each imp surveillance post to call an operator.
    • The platinum edition adds in one crystal ball (SRD) per 50 imps ordered for just a tiny extra cost of 1001 gp per imp, so that someone can scry on what the imps are seeing!

Work needed:

  • one case for the judge/sherrif. This can take between months if your state follows modern due process or 10 minutes if you have a very quick procedure.wages not included
  • one day of skilled labor for the executioner for the bargain price of 2 gpwages not included
  • one day of skilled labor for our wizard/sorcerer, costing something like 200-300 gp, please specify details with this subcontractor.wages not included

Materials needed:

  • one criminal suffices for more than one casting within 24 hours (and doesn't need to be re-payed if yearly maintenance is held less than 365.25 days from initial setup)
  • 1000 gp gem per fiend bound, equalling the number of places monitored.

As this is the cost per year, this bargain of just a bit over 1000 GP per place under permanent surveillance is hard to beat! Order now at Imp Surveillance Inc!

$$\text{}^\text{Imp-Operater & wages not included in any package.}_\text{One operator on call with knowledge of an illusion spell per 50 imps advised.}$$ $$\text{}^\text{Only Lawful Evil states with death sentence will get serviced. No guarantee for well behavior of Imps past guarantee date.}_\text{Guarantee void in presence of gods, paladins, clerics, heroes or angry citizens. All sales are final, no refunds.}$$

  • Total price for a platinum grade 50 imp system: 550500 gp initial setup, 50000 gp yearly maintenanceimps only
  • Total price for 100 imps: 1089990 gp setup, 99000 gp yearly maintenanceimps only

Operator fees, setup of a monitoring HQ, psychological therapy for the operator after prolonged exposure to imp-chatter not included

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  • \$\begingroup\$ What should the imps do to call someone in? Is there a magical effect or do they just run and find somebody in authority? \$\endgroup\$ – doppelgreener Nov 22 '16 at 15:41
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    \$\begingroup\$ did I forgot the premium upgrade?! \$\endgroup\$ – Trish Nov 22 '16 at 15:46
  • \$\begingroup\$ Maybe! Sending stones were mentioned in chat as a way for someone to remotely "call" someone else, though I don't know what those are. \$\endgroup\$ – doppelgreener Nov 22 '16 at 15:54
  • \$\begingroup\$ sending stones are basically magic-rock-walkey-talkeys \$\endgroup\$ – Trish Nov 22 '16 at 15:58
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    \$\begingroup\$ @AlbertMasclans it's a two stage thing: the imps watch without pause. If one spots something, he uses the sending stone to call an operator on call, who uses a crystal ball to scry upon that imp. \$\endgroup\$ – Trish Nov 22 '16 at 16:50
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Miniman's answer is absolutely correct in its central premise: scrying is the spell you need for this. He does a very nice job tabulating just how much wizarding power it would require to scry a location 24/7, and I'll be using those numbers.

He also suggests you get your hands on some crystal balls; I'm going to suggest you craft their equivalents: scrying mirrors. (Functionally identical to a crystal ball, but shaped as a rectangular mirror for your nice wall-mounted display.)

36 11th-level wizards can scry your target 24/7; with 56 days and 50K gp1 those same wizards can craft you a scrying mirror, operable by anyone, to do the same job. (I assume the wizards' day-rate doesn't change.)

Is that cost-effective? Depends how long you're intending to scry each location. Your threshold for when you should be investing in magitech, rather than crude arcane labor, is

$$ t_\text{threshold}=\frac{50~000\text{ gp}}{36 \times (\text{wizard day-rate})} $$

Following the 2e Castle Guide convention on pay rates I get a 11th-level wizard's day-rate of 118gp/day.2

With this your threshold is 12 days: if you're watching for more than 12 days and have the 56-day lead-time to spare, craft your surveilance system rather than outsourcing it.


1 - 50K gp: I'm assuming the "standard" very rare crystal ball, not the legendary variant(s).

2 - see What's a good pay rate...?, esp my answer at part (3), for some thoughts on why that's an appropriate scheme to use. That question, though, focuses on tier-1 characters, so it's a bit extrapolatory to use it for L11 wizards.

The calculation is: L11 wizard is "worth" the labor of (1 + 11 (from PC levels) + 47 (from spell slots))=59 skilled laborers, multiplied by the 2gp/day skilled labor rate given on PHB5e p.159.

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If you want to have a single, central system, then the spell of choice is Scrying. No other spell that allows you to watch an arbitrary location has its unlimited range. Unfortunately, it's a 5th level spell, and only has a 10 minute duration. So you're going to need a lot of high level wizards1 to get 24-hour-a-day coverage.

24 hours worth of 10 minute intervals means each location will need 144 Scryings a day. This requires some number of wizards casting in shifts for each location:

  • 144 9th-level wizards
  • 48 10th-level wizards
  • 36 11th-level or 12th-level wizards
  • 29 13th-level or 14th-level wizards
  • 24 15th-level or 16th-level wizards
  • 21 17th-level wizards
  • 18 18th-level wizards
  • 16 19th-level wizards
  • 14 20th-level wizards

Or some combination of differently-leveled wizards, obviously.

The alternative is to get some Crystal Balls. Crystal Balls allow you to cast Scrying an unlimited number of times per day, so you'll only need 1 for each location you want to view. Note that anyone can use a Crystal Ball, so your hiring requirements are pretty open2.

On the other hand, if you're ok with having a number of substations, Clairvoyance is a 3rd-level spell that allows you to watch an arbitrary location within 1 mile. As it's 3rd-level, you can recruit lower level wizards, but it has the same 10 minute duration, so you'll still need an awful lot of them - 72 3rd-level wizards, or 7 20th-level wizards casting in shifts to cover each location for 24 hours a day. (Not going to do the maths for every level from 3rd to 20th.)

Either way, you want to project what the watchers are seeing to a screen. Luckily, this is pretty simple - as long as all of your watchers know the cantrip Minor Illusion, they can make an illusion of what they're seeing. They'll have to cast it 10 times for each Scrying or Clairvoyance, but since it's a cantrip and doesn't require concentration, this isn't actually an issue.


1 Bards, Clerics, Druids, and Warlocks can also use Scrying, Wizards are just an example here.

2 If you're using Crystal Balls, and looking to recruit non-wizard watchers, any Bard, Sorcerer, Warlock, or Wizard can learn Minor Illusion. Additionally, Arcane Tricksters, Eldritch Knights, and Arcane Clerics can also learn it. On top of that, any High Elf can learn it, all Forest Gnomes know it, and anyone can learn it using the Magic Initiate feat.

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    \$\begingroup\$ Do Crystal Balls in 5th ed say anything about the scried image showing up in the ball? If so that would be "something like a screen" just on its own. \$\endgroup\$ – doppelgreener Nov 22 '16 at 12:31
  • \$\begingroup\$ @doppelgreener Unfortunately not - just that you can cast the Scrying spell, which itself uses a crystal ball/silver mirror/font of holy water but doesn't say anything about the scried image appearing in it. \$\endgroup\$ – Miniman Nov 22 '16 at 12:37
  • \$\begingroup\$ Excellent Answer! I like the sound of a high level Wizard police force of sorts. Pretty terrifying to have 14 20th Level Wizards watching and waiting... \$\endgroup\$ – Mumford451 Nov 22 '16 at 15:22
  • \$\begingroup\$ Good answer, important to note that a single casting of Nondetection thwarts this entirely. Adding Alarms and other wards from the Abjuration school would help mitigate that back door. \$\endgroup\$ – Slagmoth Nov 22 '16 at 16:14
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For lower levels, I would set up a network of alarm spells (which can be cast ritually with no resource consumption. Then when the alarm pings me, I would cast clairvoyance (3rd level spell) on that location to actually see/hear what is happening there. If I wanted to share that information I could put up a minor illusion (which would not be able to move) of the most important thing I was seeing.

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  • \$\begingroup\$ I approve of this. Presumably a single wizard would be "watching" an entire area with a large number of Alarm spells, as well as a clairvoyance/minor illusion. Somewhat similar to today's system where typically the number of cameras is far larger than the number of security watching. \$\endgroup\$ – Sh4d0wsPlyr Nov 22 '16 at 14:32
  • \$\begingroup\$ As the spell is written, there's no way to tell which alarm is going off. A group of wizards can share a single audible alarm, and each wizard can have an additional mental alarm. \$\endgroup\$ – Samthere Nov 22 '16 at 14:45
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Depending on how you want your surveillance system to function, the use of Find Familiar, and Homunculi (MM 188) to share senses could give you good aerial surveillance. A level 3 Pact of the Chain Warlock or a Wizard with a homunculus can control the location of their partner and see through their senses anywhere on the same plane. And both have flying speeds.

As suggested in other situations, the use of minor illusion can show the scene on a screen.

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I think I'd use a combination of Animal Friendship on birds, and Beast Sense, and as someone else suggested, Minor Illusion to show it on a screen or whatever.

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  • \$\begingroup\$ I reversed my downvote from earlier, but I want you to know it was 'cause I'd already changed my mind (but it was locked in). You didn't necessarily have to add the last bit. At this point everyone's going "oh yeah and do that minor illusion thing the other guy already said" since it seems to be the only solution for that anyway. \$\endgroup\$ – doppelgreener Nov 23 '16 at 0:32

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