Help me Understand the location of a created Demiplane

[RUMBLETiGER]

There is a detail about the Create Demiplane line of spells that is unclear to me, and my Google-fu has not yet found anyone else talking about this. Sorry if this has already been discussed somewhere else.

1. Does your Demiplane exist on the Astral or Ethereal Plane, or does it exist separate, it's own little universe bubble, "Off the side" so to speak of one of those Planes? For example, if I made my personal floating island, would someone who was travelling along the Astral Plane see it right there, floating as an object within the vast larger Plane, or do you need to Plane Shift specifically to my tiny Demiplane? Or is it a third possible option, that it does exist floating and visible within the Astral or Ethereal Plane, but it's an inaccessible mass from the outside on that parent Plane, and while inside you don't see the parent Plane when you look to the sky?

And my second question is connected to understanding the first.

2. Do the Cubic Feet measurements of the spell indicate:
A. the volume of space my Demiplane takes up (Which leads me to think it is it's own separate planar universe)
~or~
B. the amount of matter I can generate that makes the substance of what I end up standing on (Which suggests it existing within the Astral or Ethereal Plane and able to be found there)?

These questions stem from confusion about the wording of the spell. for example, the text:
"you decide whether the demiplane is within the Astral or the Ethereal Plane." suggests that it's a floating island of sorts in the vastness of the larger Plane.

However, the following line:
"The “walls” and “ceiling” of the plane may appear like solid earth, stone, wood, or water, or they may end in mist, a featureless void, or a similar unreal-looking border." seems to suggest that when I am on my Demiplane and fly off of it, I either encounter the walled end of my pocket universe, or I enter a vast, empty mist that is not the space of the Astral or Ethereal Plane.

The line:
"The demiplane is another plane of existence, and therefore is outside the range of any spell or ability that cannot affect or reach other planes." at first sounds clear saying it's another Plane of existence and therefore it's own bubble, until I realize it's just indicating it has the same limitations on spells that any Plane besides the one you are currently on would have.

The line:
"An ejected creature goes to the closest plane to your demiplane (usually the Astral Plane or the Ethereal Plane, but if you cast this spell on the Material Plane, the creature is sent to the Material Plane)" seems to suggest it is it's own little bubble universe, but it could also be referring to flinging someone away into the void that is the larger parent Plane.

The line:
"If a collapsing portion of the demiplane would leave one section cut off from other sections of the demiplane (for example, if there were three areas connected in a straight line and the center part expired), the stranded sections count as separate demiplanes under your control. You may reconnect these stranded sections by casting the spell again to create a linked area between the two." seems to suggest that these Demiplanes exist in a fixed spot in a larger space, suggesting they reside and therefore are visible to the parent Astral or Ethereal Plane.

I'd appreciate if someone could clear this up for me! Thanks.

~RT

 

[Simon T. Vesper]

Based on the linked spell descriptions, I'm not certain there is a way to clear this up without resorting to DM interpretation.

That said, this is my take:

I understand the question as, "Where does the demiplane exist in relation to other planes?" The spell is clear that your demiplane is a part of either the Astral or the Ethereal, because of the line you referenced. However, as the spell does not explicitly state that your demiplane is visible to travelers in either the Astral or the Ethereal, and because both these planes are (arguably) larger than any other plane of existence, I would rule that the chances of your demiplane being found visible to anyone who isn't already aware of it, is equivalent to the proverbial snowball.

As to your demiplane's relationship to the Material (or any other plane of existence), I would rule that it shares a connection with whatever plane you occupy when you cast the spell. If you're in the Abyss and you cast create demiplane, the resulting demesne will reside in either the Astral or the Ethereal (your choice) and will share a connection (or pathway) to the Abyss. (Likewise, if you cast the spell while on the Prime Material, it will share a connection with the Material plane.)

I realize this probably doesn't give you a concrete or supported answer, but I hope it at least points you in the right direction.