Major magical city defenses

[Elkad]

Help me guard my city.
Powering them by handwavium magic is fine, just needs to make some sort of sense.

Major city (probably a capital). LN (tending good) leadership.
Basically benevolent, but they expect to screen (and tax) entrances and exits heavily. Creatures who don't fit their ideal can enter, but are taxed higher and/or may draw special attention.
I don't want invasion to be impossible, I just want to know about it.
I expect to have a fair amount of smuggling via bribing guards, secret tunnels, etc, but nothing will be consistent. Just stealthing past the guards should be viable.

Stuff I've come up with so far.

Everything is at CL25 for purposes of Dispelling it (as an item, so 1d4 rounds), getting past it with NonDetection, etc.
Note: I have gone with a restrictive interpretation of Mind Blank. It does not prevent all Divinations from finding you. It prevents scrying, and mental effects (detect thoughts, detect alignment, etc). Something like Detect Undead or See Invisibility works just fine on a Mind Blanked subject. Use Non-Detection instead.

Walls.
120' high, extend 120' underground, 60' or more thick. Tunnels inside for guards.
Modified Forbiddance effect. Blocks planar travel. Covers full wall area, plus extends vertically to a height of 600'. You can teleport THROUGH it, but not land anywhere IN it.
Does not damage creatures (it's unaligned).
Password updated daily, and may differ between areas.
You can walk through it with spell resistance, but you have to check every 5'. Any square you fail to enter is forbidden to you for 24 hours.
Passwall is CL check as well. Check each square it penetrates.
Need to boost the hardness of the walls.
I specifically don't want Wall of Force effects.

Need a way to block Earth Glide. I'd like it to be something like paint you could scrape through. Can I just use a layer of wood? Coat the entire wall in Shrieker fungus?

Gatehouses.
Has same Forbiddance effect as walls.
Invisibility Purge, Detect Charm, Detect Evil, Detect Chaos, Detect Undead. All always on, and the Detect spells cause the detected subject to glow and make a humming noise. Different sound/color for each Detect Spell.
Is there a Detect Outsider I'm missing? I'd like to tax them too.
I don't want to go all the way to True Seeing, though I'll probably give a bunch of officers an item that does it a limited amount of time a day (and only works inside the city. I'll expect people to have stolen/liberated a fair amount of them for other purposes (shopkeepers, etc))

Teleportation.
Entire city is (from 120' down to 600' up) covered by a Superior Anticipate Teleportation effect. Delayed 4d4 rounds. Flashing light and loud siren (Listen DC:-20) sound at arrival point for the full duration. The light penetrates magical Darkness as an 8th level spell. Magical Silence is penetrated in the same fashion. (Simply teleporting into a room deep inside a house would work fine). Note that this is actually useful at times. You can teleport into an occupied area and know your location will warn people to move away so you have a clear landing.

Scrying.
Mage's Private Sanctum over the whole city. Modified to be penetrated by a CL check (DC40).

Flight. I want you to be able to just fly over the walls. I want you to get caught when you do.
Key areas will also have towers with nets (Fine-sized mesh) completely covering them. Steel cables with Glasssteel probably. Extend the Forbiddance over the whole city (a ceiling at the 600' level, so it intersects with the walls).

Underground. Need to cover this as well. More Forbiddance? Tremorsense? Guards on some sort of Earth Glide mount?

[flappeercraft]

You need a way to detect when someone enters so for that I reccomend this as the ultimate detection system. You can monitor everyone who enters or leaves the city.

1. Get a Simulacrum/Ice Assassin/Mindraped Formian Queen
2. Get access to DCFS
3. Switch any of the feats of the formian queen to Mindsight
4. Place in the center of the city
5. ???
6. Profit

Essentially the Formian queen has Mindsight that reaches for a 50mile radius around her. As widely known, mindsight does not require LoS or even LoE. The only thing it does not detect is Mindless things.

This way if something teleports in, sneaks in somehow or leaves. You will know and you will know exactly where they are down to the 5ft square all the way.

Edit: On the earthglide thing, earthglide does not allow you to go through metal so lead based paint and the equivalents should block someone with the earthglide spell or ability from entering.

[Elkad]

That's a little too good. I want people to be able to sneak in and out, just with difficulty. Not MindBlank difficulty (which would guard against Mindsight anyway).

I might use that for key areas though (Palace, etc).

[flappeercraft]

Actually, Mind Blank doesn't stop Mindsight. I do agree that it is a bit too broken for covering a whole city and makes it nearly impossible to sneak in.

What you could do is use things woth shorter ranges then like Couatls which have 100ft IIRC.

That or if you want the extremely broken option at some point or another, use a Spell weaver which has a 1000 mile telepathy range.

What you could do if you don't want detection systems that broken would be to use patrols with domesticated spiders, they have tremorsense albeit at short ranges.

[Elkad]

Actually, Mind Blank doesn't stop Mindsight.

That's a RAW discussion I care to skip. My interpretation is Mindblank simply makes your mind completely undetectable, and thus mostly invulnerable. Telepathy slides right over you, the same as scrying does. As I mentioned above, Mindblank does NOT make you immune to other divinations, like See Invisible. It's very good at protecting your mind though. Including from friendly telepathy - that doesn't work either while it is up.


protected from all devices and spells that detect, influence, or read emotions or thoughts That's close enough for my purposes. Mindsight detects your mind (and determines your type and intelligence). Therefore it is blocked.

[Zombulian]

You're gonna need some big ol' sentries that will be intimidating but defeatable like these guys (https://m.youtube.com/watch?v=jLaqLCnmZ2w#).

[Darth Ultron]

There are spells like Augment Object and Hardening to increase the toughness of objects and items. Plus there is the magic walls listed in the DMG/SRD.

Constructs make for great guards, as do summoned creatures, that can go after anything flying in and around the city.

If you can manage caster level 32 when casting Animate Object, then you can animate a Colossal object. In the core rules, I'm pretty sure there is no maximum size on colossal, as it is the largest size category and encompasses the entire upper end of the spectrum. So once you can animate Colossal Objects, it can be argued you pretty much can animate anything. And animate object can be made permanent, on in theory you could animate a castle.

Also Races of Destiny has the spell: Animate City.

BOED has: Celestial Brilliance: Evo, S/W/C 4, 60ft light deals 2d6 to evil outsiders every round. Lasts for Days/CL on objects. You could also make ones for other alignments.

Sacred Item/Profane Item (Complete Champion) spell. An item imbued with this spell does 7d4 (at lowest CL) damage to evil/good outsiders upon contact, no save no SR (there IS a save but it only applies to undead fleeing). It has no effect on non-evil(good)/non-outsiders and non-shapechangers, so the general populace should be safe. The duration is permanent, so you can stockpile as many of these items as you can produce. It like the Clerical equivalent of Explosive Runes.

For the underground, there is a classic: Black Puddings. Place closed caves full of them all around, or make a 'moat'. There are also other hazards and creatures that work too.

Calm Earth, from the old Wizards Spells of the Volcano protects vs earthquakes and such...and even slows Earth type creatures.

Divine zehper/flame are both low level and harm fire or cold creatures. And would great in any 'permanent' item or spell effect. You could add a 'earth' and 'water' one.

[Uncle Pine]

You're gonna need some big ol' sentries that will be intimidating but defeatable like these guys (https://m.youtube.com/watch?v=jLaqLCnmZ2w#).

I suggest magically aged (or just really old) 4th-level warrior kobolds (http://www.giantitp.com/forums/showsinglepost.php?p=19351765&postcount=16). They'll definitely be ominous, but with only 4d8 hit die!

[TalonOfAnathrax]

Every major magical city needs some kind of weather control effect. It's useful in day-to-day operations, it can be used defensively, and it help avoid insane "Control Weather cooperatively cast at CL 45" comboes that could destroy the entire city easily.

I'd suggest having teleportation/etheralness/refuge/dimension door only be possible in a few well marked (and guarded) areas. They could function like train stations/helipads.
An interesting side-effect of this could be that it would also restrict other planar/dimensional effects like Portable Hole or Bag of Holding (it would stop them from being opened within the city). So there should be a tax that you could pay to be "keyed in" to the wards for merchants and rich citizens to use - criminals could corrupt officials and have a few of their people be keyed in if needed, but things like demon invasions couldn't do this so it'd remain an effective defence.

[Tvtyrant]

The entire city is a colossal animated object that has been told to stay in one spot.This prevents teleportation as the city is an occupied space, as well as allowing the city to make AoO against people attempting to enter its space.

This also allows the city itself be protected by up to 32 crafted contingencies, everything from mindblanks to temporal stasis (rendering it indestructible).


The city is also covered in a series of Hallow spells with Protection from Energy, and the outside is covered in wall of fire generators. The hallow only grants PfE to citizens and people willing to be stamped for it, so intruders are constantly on fire.

[Goaty14]

You can teleport THROUGH it, but not land anywhere IN it.

One does not simply "teleport through". Teleport, dimension door, and etc briefly plane shift into the astral plane and then back into the material plane, not involving your petty city whatsoever. Methinks it was planar handbook that said this.

[Jay R]

The biggest threat is magic. So all around the city walls, far enough away to be where the besiegers are, there should be Contingency spells that set up an anti-magic field as soon as an offensive spell is cast. This way, a high-level caster turns off his own power as soon as he tries to attack.

[VictoriousLoL]

Although my experience was with Pathfinder, should largely work the same: I had a lot of luck with Animate Object on individual pieces of walls. In particular, I had 'backup walls' whenever I knew an enemy would be attacking from a direction and could move new walls in to replace destroyed ones. Worked pretty well. Also Walls of Force worked very well, along with permanency.