D&D 5E Standard security features of a permanent Teleportation Circle

[Saeviomagy]

Let's say I accepted all your assertions on how many people you can get through a circle in 6 seconds. Wouldn't that just make them more likely to be epic slaughtered in seconds.

Sure, if your contingent of guards stationed at your heavily used teleportation circle don't count as surprised...

If while hustling you can fit 4 people to a 5'square how many can fit when jam packed into nearest unoccupied space? You could probably wipe out all 384 with a single fireball. They wouldn't be appearing outside the ring they'd be crammed in to their own doom. and if we are going with realistic when at a hustle your distance between friends gap suddenly narrows to virtually nothing are they bumping into each orher, tripping and falling. It would be the keystone cop invasion.

I feel like this is just being contrary.

Similarly though if the world is populated with coordinated guys getting themselves through a circle in 6 seconds dropping a dozen gang planks and unloading the same number of men from a boat should take the same time. Either you can train people for maneuvers where they move in perfect unison in tight formation or you can't. Private sanctum on a boat so it's only visual tells that reveal. Unload a mile or 2 out of town in apparently 6 seconds per 300+ troops and march into town before they can respond.

And you've given tons of advanced warning because you've been visible the whole way, plus it took you days to travel the required distance from <place where an army is not considered a threat to our city>.

A mundane force of footsoldiers can be opposed by another mundane force of footsoldiers, and if you're defending a city, the defender generally has a significant advantage.

But some demons and undead are really hard to stop with just mundane forces.

On the low-CR end, barlgura and quasits can become invisible, shadow demons can pass through walls and are stealthy, wraiths can go through walls and animate their victims as spectres

And high-CR demons can teleport, and mummy lords and liches are totally immune to mundane weapons!

Sure, but it's probably a lot easier to find enough troops to defend your city against a 2000-man army than to find a party of adventurers high enough level to deal with a nalfeshnee, marilith, balor, mummy lord, or lich. 13th+ level people just aren't that common.

The fact that you have a civilization would suggest that they are common enough.

In a high-magic world, I don't think you'd have city walls, just as modern cities don't.

If there are enough wizards capable of casting teleportation circle to make permanent teleportation circles important to trade (which implies a very-high-magic world with lots of high-level spellcasters), then war is going to be dominated by high-level characters and powerful monsters, not medieval-style closely-packed armies that are highly vulnerable to area effects.

The thing is that a wizard capable of casting teleportation circle 1/day is only 9th level. He's likely to die a grisly death if he faces up to even 100 soldiers unless they're obliging enough to stand in a 20ft circle for him.

 

[RangerWickett]

In the ZEITGEIST adventure path, rather than teleportation circles there are teleportation beacons. If you try to teleport anywhere within 3 miles, and the total distance of your teleport is more than 1 mile, you get shunted to the beacon.

In the city of Flint, the teleportation beacon is in the middle of a military base, surrounded by a cage, with a 10 ton stone weight above the arrival spot, in an underground bunker. Protocol demands that you notify the base at least a day in advance (usually by casting sending to one of a handful of couriers in the city, who then deliver a formal request with your estimated time of arrival). If it's urgent you can send directly to the base staff. If someone arrives without pre-authorization, they have about ten seconds to explain themselves before they get crushed. Even then, an alarm goes off and the whole base is put on alert.

By contrast, the city of Seobriga was once ruled by a dragon who was unafraid of mere humans and didn't care if people came and went or killed her subjects. So she had a teleportation beacon placed in the center of the main city square. Nowadays, a couple centuries after the dragon was deposed, the locals see it as a sign of their welcoming nature that they don't lock up their teleportation beacon, though they do have staff nearby to inspect arrivals, levy tariffs, and sound an alarm if anyone dangerous arrives.

On the island of Mutravir, there is a teleportation circle on a plateau that overlooks choppy, unnavigable water. From there stairs lead up to an abandoned mansion. If you want to meet with the denizens of that mansion, teleporting in is just the first step. You then need to know the passcode to the local pocket dimension, and speak it quickly before umbral basilisks turn you to a scorched silhouette on the cliff face.

 

[S'mon]

IMCs I limit teleport circle to 8 human-sized people per casting; this lets it performs its in-game function, without arguments around how many people can run through the portal before it closes.

 

[Ahglock]

Sure, if your contingent of guards stationed at your heavily used teleportation circle don't count as surprised...

I suspect surprise would wear off quicker than the invading force could organize after a teleport. I mean chances are they are on guard only for that purpose, so its not like they will be shocked for minutes. But if you were that worried about it a glyph of warding or 4 would react for you, fireball/circle of death activates if more than X armed people show up. Still assuming the circle is in a pit like i said, probably 100 feet to the nearest wall, the defenders drop the gate so the invaders are trapped inside and archers with heavy cover begin murdering everyone inside with their far superior position. You don't have to have that many there, just a lot on call for when the alarm sounds. Heck even if i wasn't worried about invaders I'd have the same set up for merchants to have to check in with a secondary nearby area for a market.

I feel like this is just being contrary.

Not in the slightest. I've run in packs in long and short distance competitions when one person falls a dozen might fall with him. Tight packed squad teleporting in where the distance between each of them, orientation, speeds will suddenly change with random obstacles like people, terrain changes etc., I can't see how that ends well for the invaders . I honestly think there is a much much higher chance of hundreds of men on the floor trying to get up than there is of this working out in a coordinated fashion. I'd be fine with it happening in game as making the storm troopers look like a threat even if they suck is a standard bit of stroytelling. But if you want to get realistic about how many people you can cram through a portal, well realistically suddenly being teleported while running in tight packs probably doesn't end well no matter how much you trained in that maneuver as my location isn't static its nearest unoccupied, the location I'm running into isn't static, one person falls and now you are teleporting into nearest unoccupied space with a tripping hazard at a run. But if this is a feasible maneuver sure up the security a bit, add caltrops, a ring of spears they are running into, difficult terrain, a pit, or moat some basic mundane security would break the charge quickly and set them up to be murdered by archers.

And you've given tons of advanced warning because you've been visible the whole way, plus it took you days to travel the required distance from <place where an army is not considered a threat to our city>.

Ships have been landing on shores with no warning for thousands of years, its probably more common for them to be able to do so than actually be seen. And its not like you have to have a flag waving, we are invading you, just show up in merchant ships in the harbor its a time tested strategy. Raiders have successfully raided port towns by just sailing in pretty much since boats existed. Border security especially coastal is a relatively recent phenomena. As for the time wasted, sure teleport is more convenient, I'm just not sure its that much bigger of a vulnerability than just being a port town in the first place. Cheaper, faster, and unless someone sabotages the permanent circle they will remain well supplied to lay siege at least as long as your 50GP a pop can hold out. But a bunch of boats sailing into your harbor and suddenly unloading troops instead of the expected tators seems just as bad.

 

[Erik Westmarch]

How are people envisioning this spell? A circle that anyone who enters they get transported from?

What a great observation! The spell doesn't say. There's really nothing in the spell description that specifies the size or shape of the portal, other than that it's inside the circle. I'd say it's 100% the DM's discretion how they want to run it in their game. The only size given is the size of the Circle (10' diameter), but there's no RAW link between the size of the circle and the size or shape of the portal.

And of course any answer you give here will have a significant effect on any discussion about how many people can run through the thing in a round.

I was picturing a verticle 10'x10' square like you were but it could just as easily be a small oval, cube, or the full circulate border of the circle (like the outside boundary of a cylinder).

And there's a separate (unanswered) question as to whether you can enter the portal from only one side or both. Or from all sides, in the case of a 3D shape.

Though how this is much worse than them unloading a boat full of troops I'm not clear on.

Mainly the difference is the location of the Circle. If it's insider the inner Keep, it bypasses all your wall and sentries, unlike a boat.

In the ZEITGEIST adventure path, rather than teleportation circles there are teleportation beacons. If you try to teleport anywhere within 3 miles, and the total distance of your teleport is more than 1 mile, you get shunted to the beacon.

What a great idea! I love it. As a House Rule I might allow that any Permanent Teleportation Circle can optionally act as a Teleport Beacon too. I would have it effect all true Teleport spells (regardless of distance). If you don't want to be sucked into you you'd stuck with Misty Step, Dimension Door, etc.

A fun side project would be creating "options" that could be added to Permanent Teleportation Circles.

• Beacon would be one.
• Alarm would sound a loud chime or other noise to announce its use.
• Dispel hits all active spells or effects with Dispel Magic

You could also have ones that aren't obviously beneficial or defensive, but represent some sort of defect in the Circle, such as Animate Object randomly effecting 10 items in the group that then start attacking you.

In a high-magic world, I don't think you'd have city walls, just as modern cities don't.

Not to derail the thread, but disagree. A D&D city would need defenses against flying and magical enemies, but walls would still be useful against mundane threats like invading armies, goblins, bandits, etc.

Real-world cities only got rid of their walls once artillery reached a certain level of range and power. D&D may have wizards, but the standard implied setting doesn't have mass produced artillery. Your campaign may vary.

 

[Khisanth the Ancient]

The fact that you have a civilization would suggest that they are common enough.

Not necessarily. Just because high-level adventurers exist in sufficient numbers to balance out super-powerful monsters on a large scale, doesn't mean any particular city or barony or whatever can rely on them in its defenses. People that powerful aren't likely to be at the beck and call of local lords or mayors.

Whereas anybody with sufficient population in their domain can raise an army.

And fiends and stuff are very rare unless someone is intentionally summoning them, since they're generally on the Lower Planes, so their general rarity doesn't mean you don't have to worry about them being specifically summoned for a war.

The thing is that a wizard capable of casting teleportation circle 1/day is only 9th level. He's likely to die a grisly death if he faces up to even 100 soldiers unless they're obliging enough to stand in a 20ft circle for him.

Sure, but if you have one 9th level wizard, how many 5th+ level ones capable of casting fireball/lightning bolt do you have? Probably enough to drive the enemy to not use the kind of tightly packed formations which IRL were important (as I understand it) to stop cavalry charges. That already changes tactics pretty significantly.

Also, you need a significant number of wizards of 9th+ level in the world to make teleportation circles economically important. If there are only a small number of 9th+ level characters in the world, they won't be "wasting their time" with mere commerce -- they'll be combating great threats, acting as rulers' champions/court wizards/whatever, ruling domains in their own right or running thieves' guilds/magical academies/great temples, off doing high-end magical research or unpicking the secrets of divinity, etc.

 

[Ahglock]

Well to be fair, if I weren't a adventuring or otherwise traveling 9th+ wizard and someone else wanted to cough up the 50GP a day + some pain in the butt money. Then throwing 1 minute of my time once a day for a year doesn't seem that outlandish. Especially since I'll find it useful for myself. Assuming 9th+level wizards are in your town and your town can afford 50GP+ a day it seems like a reasonable investment for trade purposes in some cases. Probably not for most towns, but trade hubs sure. The big issue for trade is it not only assumes the town has a mage to set it up but that there are enough mages to open a portal to transport goods. Some setting sure, but magic heavy eberon at least initially was fairly low level for the NPCs. No idea if its still that way, FR sure probably enough mages in guilds, towns, at the local tiki bar to pull it off.

 

[Lehrbuch]

In a high-magic world, I don't think you'd have city walls, just as modern cities don't.

True, it might not be a literal wall that surrounds the city.

Nonetheless, there will still be some of nominal perimeter. Which could be a national border or a city-state (or something else) border depending on whether nations or city-states (or something else) are the main political unit.

 

[Saeviomagy]

IMCs I limit teleport circle to 8 human-sized people per casting; this lets it performs its in-game function, without arguments around how many people can run through the portal before it closes.

I think this is pretty much the perfect way to limit the effects of the spell on a campaign world, although I would probably be a bit more vague in the interests of being more generous without it becoming problematic.

 

[Dausuul]

Put it in a room deep underground, with a single narrow stairway out and heavy iron doors, and an alarm spell. When you arrive, the spell alerts the wizard on duty above, who casts clairvoyance (I assume if you can get a 9th-level wizard to cast every day for a year to make a PTC, you can keep a 5th-level wizard on staff to monitor it). The wizard checks to see if everything looks on the up-and-up. If she thinks it is, she sends the guards to open the doors for you. If she doesn't, she triggers a slew of traps to annihilate you.