Demiplane uses? [5e]

[PIELIKEI]

Trapper:
So this is an interesting trap that I want to test out the effectiveness of. It might only work on creatures that are Medium/Large or smaller though and is pretty expensive to create. The spells are divided into 2 groups: preparation which can be cast at anytime, and activation which can be cast to trigger the trap.

Preparation:
Demiplane (lvl 8): Create a Demiplane made out of wood.
Glyph of Warding (lvl 3): Fire explosives 30 feet from the entrance
Antimagic Field (lvl 8): Centered at entrance
Glyph of Warding (lvl 8): To house the AF: On a stone plate nailed/glued to another stone plate: the glyph is inside the plate discus thing
Wall of Force (lvl 5): Surrounding the AF
Glyph of Warding (lvl 5): To house the WoF: On a stone plate nailed/glued to another stone plate: the glyph is inside the plate discus thing

In total 3 lvl 8 spells and 2 lvl 5 spells, 1 lvl 3 spell. Castable at lvl 15 over 2 days.

Activation:
Enlarge/Reduce (lvl 2) (optional to make large creatures fit).
Demiplane (lvl 8)

How the trap works:

Reduce an enemy to Medium.
Cast Demiplane at their feet (Demiplane doesn't specify whether the door starts open/closed. If the door starts closed, have your cleric ready a "Thaumatury" action to open the door as I'm sure it isn't locked)
The enemy falls through the door
Once the enemy falls through the door, the glyph of warding goes off setting the room on fire, as the trap is 30 feet away and has a damage range of 20, the enemy doesn't get a save and cannot be blown back out through the trap.
Triggering the first glyph will trigger the other two glyphs: antimagic field and wall of force both surrounding 10 feet of the exit

Since the demiplane spell is inside the antimagic field, the demiplane spell fails and the door is destroyed.
Since the room itself is on fire, I'm going to assume the enemy will be on fire too taking 1d6 unavoidable damage each turn (reflex save puts the fire out, but since the entire room is on fire, he catches on fire again immediately)
Or just fill the room with water and drown them.
You could probably get rid of the wall of force if the enemy isn't magic.
This is a pretty expensive way to kill someone but I don't think it has any obvious ways to avoid it right?

Room of Glyphs:
Much simpler than the previous one. s the demiplane is a separate plane, things inside the plane don't "move" using an 8th level spell can grant you your own room of glyph bombs as the glyphs are never moving more than 10 feet from its original location. Use with a targetted spell to go off at any hostile in range (such as magic missile) means that the glyphs never have to move just throw them in a buckets and when you cast demiplane and open the door, you have 100s of magic missiles shooting out of the door.

Fall damage dungeon shield:
A simple one here as well. Demiplane will create a door that leads to a demiplane but doesn't specify where in the demiplane the door has to be. Link your shield to the ceiling of the demiplane. Bashing enemies can trap them in your demiplane... assuming they don't fly or aren't high level mages. Each day open a new demiplane, after a month, go back to your first demiplane and collect the loot.

Death Defied:
Now this one may depend on the wording of the spell a little too much. Create a demiplane. Close your eyes and scribble on the wall a bit... or a lot. Or randomly fabricate 3 or 4 objects. Keep cloning yourself for immortality! You can come back to the demiplane at anytime because you created it with a previous casting of the spell. Other creatures however, have to guess the exact nature/contents of the demiplane to enter it. Because you randomly scribbled on the wall or have 4 random objects in there, it is going to be pretty damn hard for someone else to get to it. For annoying DM's this would also be an annoying as hell place to store a lich's phylactery


What do you guys think? Will these work as intended?

[JeffreyGator]

Trapper:
So this is an interesting trap that I want to test out the effectiveness of.
(snip)
assuming they don't fly or aren't high level mages. Each day open a new demiplane, after a month, go back to your first demiplane and collect the loot.

If you are level 15+ and fighting level appropriate stuff, assuming lack of fly ability might be a bit much. Not too many things at that level are going to be that affected by a well prepared pit trap.

Definitely creative ideas.


Death Defied:
Now this one may depend on the wording of the spell a little too much. Create a demiplane. Close your eyes and scribble on the wall a bit... or a lot. Or randomly fabricate 3 or 4 objects. Keep cloning yourself for immortality! You can come back to the demiplane at anytime because you created it with a previous casting of the spell. Other creatures however, have to guess the exact nature/contents of the demiplane to enter it. Because you randomly scribbled on the wall or have 4 random objects in there, it is going to be pretty damn hard for someone else to get to it. For annoying DM's this would also be an annoying as hell place to store a lich's phylactery


What do you guys think? Will these work as intended?

Storing clones in a demi-plane is a pretty standard use. Unless someone has been to your plane, I think it always by default pretty hard for them to figure out how to get there. This should work.

[PIELIKEI]

Thanks for the feedback! The first one though would be for higher level creatures only as it is hard to prepare and only works on 1 creature or a couple of creatures in a clump. The pit trap is mainly used for one shotting weak mobs or fighter archetypes.

Are there anyother ways people use Demiplane?

[JeffreyGator]

A demiplane is your house essentially (2700 SQFT with 10 foot ceilings) and 1-2 times per day you go open a door wherever you are to go back and forth.

Say you recover a dragon hoard. You cast demiplane and can shovel gold in for an hour and then walk out and cast demiplane back at the bank/moneychanger later on.

Or it is a Trojan horse. You stick 100 Soldiers into it. You wait a day, sneak over a wall or teleport somewhere. Let your minions out. they wreak havoc for an hour. You all go back into your plane and are gone. The next day you can teleport to the Soldier's home open the plane and let them out. A cleaning crew goes in and leaves after an hour since they made a mess in your house.

Lots and lots of utility.

[AmayaElls]

Death Defied:
Now this one may depend on the wording of the spell a little too much. Create a demiplane. Close your eyes and scribble on the wall a bit... or a lot. Or randomly fabricate 3 or 4 objects. Keep cloning yourself for immortality! You can come back to the demiplane at anytime because you created it with a previous casting of the spell. Other creatures however, have to guess the exact nature/contents of the demiplane to enter it. Because you randomly scribbled on the wall or have 4 random objects in there, it is going to be pretty damn hard for someone else to get to it. For annoying DM's this would also be an annoying as hell place to store a lich's phylactery



A demiplane is your house essentially (2700 SQFT with 10 foot ceilings) and 1-2 times per day you go open a door wherever you are to go back and forth.

I always think when using this as a house for your entire party you could get each member of your party to hide a random object somewhere or personalise their areas in some way. That way no member of the party can know the exact shape of the plane, whereas I could see something with telepathy maybe taking the knowledge of your plane and its random objects from you. I like the idea of using it as a multi storey house quite a lot, but having a jail demiplane and a loot demiplane also seems useful to me.

[RulesJD]

1. Get Animate Dead spell.

2. Stuff as many undead into the Demiplane as will fit (lots).

3. Just leave them there, doesn't matter if you lose control of them.

4. In battle, cast Demiplane and have some sort of bait.

5. Watch has a metric ton of zombie/skeletons pour out over your enemies.

[Segev]

If you're willing to devote a 9th level spell slot, as well as an 8th, you can actually cast demiplane twice in one day, so you could load and unload it that way.

And there's the option of working with another caster who knows the precise nature of the "transport" demiplane.

Heck, a couple of high-level casters could deliberately share one and use it to exchange items. Of course, teleport is cheaper, but demiplane is the semi-truck version.

[RulesJD]

Also, make sure if you're using the Demiplane for your Clone (one of my AL Wizards does this now), that you also setup a Glyph of Warding (Banishment) to be trigger by a special pass phrase.

It's the easiest way of getting back to the Material plane. You could also do a Plane Shift, but who wants to go through all that trouble?

[Segev]

I could be mistaken on this one, so please feel free to discuss and/or correct this interpretation, but I believe that astral projection now forces your real body to re-manifest as a means of preventing 3e tricks of astral projecting to your own plane just to protect your body from death. However, reading the DMG (which I recently purchased), there was a bit on astral projection to other planes suggesting that your real body doesn't actually get sucked down the silver cord when you project it onto a plane other than the one from which you're projecting. It even talks about how your silver cord has to be cut to kill you, because otherwise your "death" just sends you home.

Perhaps you can use your clone-storing demiplane as a place from which to astral project, as well, so that you're not projecting from one plane to the same one, and thus gain the anti-death benefits.

[JoeJ]

Also, make sure if you're using the Demiplane for your Clone (one of my AL Wizards does this now), that you also setup a Glyph of Warding (Banishment) to be trigger by a special pass phrase.

It's the easiest way of getting back to the Material plane. You could also do a Plane Shift, but who wants to go through all that trouble?

If the clone was grown inside the demiplane, however, wouldn't that be its native plane?

Also, the fact that Banishment doesn't let the caster decide where on the plane the target winds up doesn't make it useless, but it might lead to some amusement.

[Segev]

If the clone was grown inside the demiplane, however, wouldn't that be its native plane?

Also, the fact that Banishment doesn't let the caster decide where on the plane the target winds up doesn't make it useless, but it might lead to some amusement.

When the clone activates (due to your death), it is you. Your home plane is the Prime. So banishment will send you home.

[PIELIKEI]

Also, make sure if you're using the Demiplane for your Clone (one of my AL Wizards does this now), that you also setup a Glyph of Warding (Banishment) to be trigger by a special pass phrase.

It's the easiest way of getting back to the Material plane. You could also do a Plane Shift, but who wants to go through all that trouble?

I always thought banishment sent you randomly back to your home plane. How do you choose where to end up? Plane Shift is powerful because you can draw magical circles in safe locations in your plane and teleport to them so you know exactly where you are going to end up.

[RulesJD]

I always thought banishment sent you randomly back to your home plane. How do you choose where to end up? Plane Shift is powerful because you can draw magical circles in safe locations in your plane and teleport to them so you know exactly where you are going to end up.

Banishment doesn't say whether it's a random location, where you were last on that plane, etc. I've yet to have DMs have a problem with returning to my last location on the Material Plane.

With that said, worst case scenario just drop a Teleport spell (now that you're back on the Material plane) and you are imminently familiar with your own body's location.

[Segev]

Banishment doesn't say whether it's a random location, where you were last on that plane, etc. I've yet to have DMs have a problem with returning to my last location on the Material Plane.

With that said, worst case scenario just drop a Teleport spell (now that you're back on the Material plane) and you are imminently familiar with your own body's location.

Even if it's a random location, given that you might want to teleport to a number of different locations, depending on the conditions which killed you, you probably want at least a teleportation circle available when you wake up, and not to have to worry about spending an 8th level slot getting back (when a pre-prepared spell effect can do it for you).

[RulesJD]

Even if it's a random location, given that you might want to teleport to a number of different locations, depending on the conditions which killed you, you probably want at least a teleportation circle available when you wake up, and not to have to worry about spending an 8th level slot getting back (when a pre-prepared spell effect can do it for you).

Do you mean a teleportation circle in the Demiplane? Because that sadly won't work as it can't go across planes.

However, if you meant having them on the Material Plane that's just common sense wizarding.

[JoeJ]

Banishment doesn't say whether it's a random location, where you were last on that plane, etc. I've yet to have DMs have a problem with returning to my last location on the Material Plane.

With that said, worst case scenario just drop a Teleport spell (now that you're back on the Material plane) and you are imminently familiar with your own body's location.

Although if you've just been killed, spell slots might be an issue. (You could rule that the Clone wakes up with all spell slots restored, but I have a feeling that your players will be grabbing torches and pitchforks the first time the BBEG that they just killed returns a few seconds later, fully recharged.)

[Segev]

Do you mean a teleportation circle in the Demiplane? Because that sadly won't work as it can't go across planes.

However, if you meant having them on the Material Plane that's just common sense wizarding.Well, yes, but it bears mentioning the common sense wizarding just for completeness.


Although if you've just been killed, spell slots might be an issue. (You could rule that the Clone wakes up with all spell slots restored, but I have a feeling that your players will be grabbing torches and pitchforks the first time the BBEG that they just killed returns a few seconds later, fully recharged.)

Nah, the beauty of waking up in your demiplane is that, if you are tapped out, you can take a long rest before returning.

[Vogonjeltz]

2.Cast Demiplane at their feet (Demiplane doesn't specify whether the door starts open/closed. If the door starts closed, have your cleric ready a "Thaumatury" action to open the door as I'm sure it isn't locked)

The spell seems to assume it starts closed as the first phrase about it is "when opened". But otherwise, I'm on board with this idea.

Another possibility. As a suggestion have them go and wait in that room (demiplane) for 2 hours. A perfectly reasonable request with a very specific time limit that results in their being trapped forever (provided they can't plane shift and don't have their own clone). Provided you can charm the opponent, that's pretty good as a method of imprisonment. (Granted, it's only possible for a very high level caster who can actually create a demiplane, and one that has no allies at all who can help them).

[PIELIKEI]

The spell seems to assume it starts closed as the first phrase about it is "when opened". But otherwise, I'm on board with this idea.

Another possibility. As a suggestion have them go and wait in that room (demiplane) for 2 hours. A perfectly reasonable request with a very specific time limit that results in their being trapped forever (provided they can't plane shift and don't have their own clone). Provided you can charm the opponent, that's pretty good as a method of imprisonment. (Granted, it's only possible for a very high level caster who can actually create a demiplane, and one that has no allies at all who can help them).

That is true, however the thaumaturgy cantrip can slam a door open if it is unlocked, so you can have a cleric ready that action. Plus this trap should work on wizards too because of the antimagic field.

[Segev]

I always read "when opened" to mean "as soon as the spell is cast." That is, it is the spell that opens the demiplane. The plane persists, closed, even when the spell is inactive.

[Sigreid]

More common sense stuff, but your clone house demi plane should be stocked with an ample supply of food and water, gold, a spell component pouch with components for all of your spells, copies of your spell books, a comfy bed, and spare equipment such as weapons and armor you may be able to use, etc. Really, it should be an extra dimensional cross between a bunker and a bug out bag.

[PIELIKEI]

More common sense stuff, but your clone house demi plane should be stocked with an ample supply of food and water, gold, a spell component pouch with components for all of your spells, copies of your spell books, a comfy bed, and spare equipment such as weapons and armor you may be able to use, etc. Really, it should be an extra dimensional cross between a bunker and a bug out bag.

I would actually vote against it, in fact, I wouldn't even put all my clones in the same demiplane. Because of complete lack of restrictions on how many demiplanes you have and the fact that it costs an 8th level spell whether you are creating a new demiplane or just revisiting one, I would rather have a shell game than fortress: a little bit of food in 100 demiplanes rather than an all in one package. That way I never have to come back to my bunker and realize someone got in and trashed my place. And if someone follows me to a demiplane, make a mental note to never use that demiplane again. Password protect my demiplanes with a nonce scribbled on the wall. And rotate my demiplanes by allocating before hand and deallocating them when I'm done (that is, if I finished all the food in a demiplane, create a new one with a new nonce rather than restocking it).

I wonder if the universe would run out of memory if everyone did that?

[Segev]

I wonder if the universe would run out of memory if everyone did that?

Not before you did, I'm sure!

[PIELIKEI]

Not before you did, I'm sure!

The beautiful thing about demiplane is that while other people have to know the exact contents of the demiplane, you don't.

Just have a couple of pointers in your memory. i.e. Food 1, Food 2, Food 3, Clones 1, Safehouse 1, Zombie Hoard 1, Armory 1 etc...
And whenever you create a new demiplane allocate it, whenever you are done with it, delete the pointer.
While the demiplane hasn't disappeared, you just don't have a pointer to it. Unless their is a way of garbage collecting/freeing demiplanes

[Sigreid]

I would actually vote against it, in fact, I wouldn't even put all my clones in the same demiplane. Because of complete lack of restrictions on how many demiplanes you have and the fact that it costs an 8th level spell whether you are creating a new demiplane or just revisiting one, I would rather have a shell game than fortress: a little bit of food in 100 demiplanes rather than an all in one package. That way I never have to come back to my bunker and realize someone got in and trashed my place. And if someone follows me to a demiplane, make a mental note to never use that demiplane again. Password protect my demiplanes with a nonce scribbled on the wall. And rotate my demiplanes by allocating before hand and deallocating them when I'm done (that is, if I finished all the food in a demiplane, create a new one with a new nonce rather than restocking it).

I wonder if the universe would run out of memory if everyone did that?

If I remember right (AFB) you can only have one clone of a person at a time, so wherever you wake up you should have everything you need to be ready to go. Other than that, I agree with you. Every successful adventurer should take the time to set up safe houses. Sooner or later they are going to tick off something too powerful to just curb-stomp.

[Vogonjeltz]

I always read "when opened" to mean "as soon as the spell is cast." That is, it is the spell that opens the demiplane. The plane persists, closed, even when the spell is inactive.

It creates a door (not an "open door" just a "door") that, when opened, goes into the other plane. If it said it opens a door, or creates an open door, sure I'd agree, but it leaves it only at creating the door, and then goes on to say when it opens, which as far as temporality goes suggests the door is closed to begin with.

[Saeviomage]

The beautiful thing about demiplane is that while other people have to know the exact contents of the demiplane, you don't.

You can take that to an extreme. If you can get a hold of a random object then without looking at it you can put it in the demiplane and cast sequester on the object.

Now the object is in the demiplane, frozen in time, invisible and undetectable. The only person who can get into that demiplane is you, and even you cannot find out what object is in it. And neither can anyone else.

The trickiest bit is getting a hold of a random object. Any suggestions?

[Segev]

It creates a door (not an "open door" just a "door") that, when opened, goes into the other plane. If it said it opens a door, or creates an open door, sure I'd agree, but it leaves it only at creating the door, and then goes on to say when it opens, which as far as temporality goes suggests the door is closed to begin with.

You could be right; I don't have the spell in front of me right now. I do find it interesting that "door" means it is a fully-functional, opening-and-closing door, but "image" means only a narrow subset of the things that are part of the image, though.

No, not debating that here. Just odd how the definitions shift. Again: you could well be right about demiplane.

[JoeJ]

Death Defied:
Now this one may depend on the wording of the spell a little too much. Create a demiplane. Close your eyes and scribble on the wall a bit... or a lot. Or randomly fabricate 3 or 4 objects. Keep cloning yourself for immortality! You can come back to the demiplane at anytime because you created it with a previous casting of the spell. Other creatures however, have to guess the exact nature/contents of the demiplane to enter it. Because you randomly scribbled on the wall or have 4 random objects in there, it is going to be pretty damn hard for someone else to get to it. For annoying DM's this would also be an annoying as hell place to store a lich's phylactery

How secure this is depends on the DM's judgment of how precisely another caster has to know the contents in order to access that demiplane, and how much of that information is known by deities that can be contacted with appropriate divination spells.

[Segev]

How secure this is depends on the DM's judgment of how precisely another caster has to know the contents in order to access that demiplane, and how much of that information is known by deities that can be contacted with appropriate divination spells.

I think a nondetection would protect against divination magic, at least.

[PIELIKEI]

How secure this is depends on the DM's judgment of how precisely another caster has to know the contents in order to access that demiplane, and how much of that information is known by deities that can be contacted with appropriate divination spells.

Taking an entire year you can cast Mordenkainen's Private Sanctum around your entire demiplane. With all effects.
Scribble on it randomly with invisible ink (or lemon juice or something).
To teleport in or out relies a lot on interpretation/DM discretion (this is how I interpret it):

Plane shift requires you to teleport to an empty space; you can't plane shift into a wall (dm discretion as the spell never mentions that it has to be an unoccupied space if there isn't a magic circle)
Plane shift will fizzle out if and only if there is no place to go. If there is such a place, you will be teleported there rather than the spell fizzling out (as above, not actually mentioned in the spell itself)
Glyph of warding spells can be triggered from anywhere: it doesn't mention where you trigger from, however the spell cast must be cast from the glyph
Conjured Woodland Beings instinctively know your voice; otherwise if you cast it in battle, they wouldn't know who to listen to.
Conjured Woodland Beings would follow your instructions regardless of actually being able to see you if it is given in your voice.
Conjured Woodland Beings count as a hostile spell for glyph of warding
You can carve through the wood surrounding your demiplane
Teleportation spells connect two points in space and therefore neither extend nor is cast through. That is, if I stand on one side of an antimagic field, I can teleport to the other side of the field as my magic does not travel through the field.


To get out:

Cast Leomund's Tiny Hut
Plane Shift out from inside the hut
As Mordenkainen's Private Sanctum is a spell effect, it doesn't permeate through the hut, as teleportation neither extends through the hut nor is it ever cast through the hut, the hut doesn't prevent the teleportation spell.
When you leave your demiplane, the hut collapses as you left the area which prevents entry by others


To get back in there are two parts, a setup and an execution.
Setup:

Carve a small wooden hole into the side of the wall outside of the private sanctum.
Put a light wooden statue of yourself into the hole. The space is now occupied and all teleportation inside will fail because every space is either occupied or inside the Sanctum and you can't teleport in there.
Cast Magic Mouth to tell the creatures to move the wooden statue if such woodland creatures should appear (and they were conjured by a glyph that you inscribed... can't hurt to be careful).



Execution
Every time you leave, inscribe a glyph with Conjure Woodland Beings to cast it when you say a password (specify that it only casts when you say the password)
Once the creatures are summoned, the magic mouth goes off and the critters remove the light statue from it's place.
Cast Demiplane to get back in.
Replace the Statue when you are done.


There, you are now immune to things like people plane shifting in or divination effects. They still can't shift into your demiplane because they don't know what is inside, and you can't teleport into the demiplane because everything is either obscured or inside a sanctum

[JackOfAllBuilds]

What about with the Forbiddance spell?
Also, does simply stepping through the doorway of a summoned Demiplane count as interplanar teleportation or using a portal?

" For the duration, creatures can't teleport into the area or use portals, such as those created by the gate spell, to enter the area. The spell proofs the area against planar travel, and therefore prevents creatures from accessing the area by way of the Astral Plane, Ethereal Plane, Feywild, Shadowfell, or the plane shift spell."

[PIELIKEI]

What about with the Forbiddance spell?
Also, does simply stepping through the doorway of a summoned Demiplane count as interplanar teleportation or using a portal?

" For the duration, creatures can't teleport into the area or use portals, such as those created by the gate spell, to enter the area. The spell proofs the area against planar travel, and therefore prevents creatures from accessing the area by way of the Astral Plane, Ethereal Plane, Feywild, Shadowfell, or the plane shift spell."

Not sure about planar teleportation, but definitely planar travel.

[FatherLiir]

My personal favorite is something I just discovered; Deep Rot. A demiplane filled with undead, that act as a computer.

[tieren]

I also thought you could get into some fun shenanigans if you filled one with water (like opening the entrance in the sea). You could then use it for instant flashfloods, putting out fires, summoning water elementals in the desert, etc...

[MaxWilson]

Nah, the beauty of waking up in your demiplane is that, if you are tapped out, you can take a long rest before returning.

A long rest, yes, plus you'll want to re-cast Clone before leaving the demiplane.

I like the idea of a demiplane filled with water... but unfortunately I can't persuade myself that a 30' cube is enough water to be worthwhile. On the one hand, yes, it's 837 tons of water. On the other hand, it's not enough volume to flood more than a room or three, especially if it quickly drains.

And drowning in 5E takes forever.

[Segev]

A long rest, yes, plus you'll want to re-cast Clone before leaving the demiplane.Assuming you don't have any backup clones already in place, anyway. Nothing prevents you from having double-redundancy. And this would let you hurry back if you needed to, knowing you still have one more.


I like the idea of a demiplane filled with water... but unfortunately I can't persuade myself that a 30' cube is enough water to be worthwhile. On the one hand, yes, it's 837 tons of water. On the other hand, it's not enough volume to flood more than a room or three, especially if it quickly drains.

And drowning in 5E takes forever.

It's enough water for purposes like summoning water elementals.

If you're an illusionist, your mirage arcane is going to be a more useful source of environmental water, since you could cause an entire castle to be underwater with it if you needed to. Sure, it's illusory, but that really doesn't matter all that much with how powerful the tactile illusion is. (If you're not an illusionist, the 10 minute casting time is prohibitive for casual use.)