Extraplanar Weak Point

In most multiversal models, including the Standard Multiversal Model, Yendalism, and the multidimensional web model of the elven philosopher Avariel, the planes are thought to exist in a complex space that cannot be straightforwardly depicted, where distance between planes is not a simple linear measure. Thus, as metaphorically described by Gaius Devarro, there are always “places in our physical world of the Material Plane where the walls between planes are thin and you can hear the shouting of the worlds next door if you listen.” These are typically known as Extraplanar Weak Points.

These are not portals: as described by the foundational work On Metaphysics, portals between planes are themselves infinitely long and infinitesimally short at the same time, tunnels that defy logical explanation. Indeed, careful experimentation recorded in the seminal work On the Nature of Extraplanar Travel showed that it is no easier to traverse across planes at extraplanar weak points than elsewhere. However, there are many recorded tales of strange magic being common at these places, thought to reflect the ability of extraplanar energy to leak across planar boundaries in places where the planes are unusually close together.

Many planar geographers have sought understand the properties of these extraplanar weak points. Ishara Venn, studying elemental vortexes, claimed they were akin to long-lasting elemental vortexes: connections caused by action on the Material Plane that draws extraplanar energy and in doing so draws a particular plane closer. Others, including the elven philosopher Avariel, have argued that most extraplanar weak points are scars of the Riving, places where the planes were never fully separated by the Divine Presence. And the lizardfolk epic The Endless Currents describes the Tharzen Anzinakoa, the Firstborn of the Lizardfolk, as weaving strands of energy and spirit into the Material Plane, knitting the multiverse together with threads of connection to prevent the shattering of the cosmos, although whether this is intended to represent a metaphysical truth or a metaphor is never clarified. The exact nature of these extraplanar weak points remains an unsolved mystery in planar geography.

Planar Dualists and Extraplanar Weak Spots

Followers of planar dualism, unlike most other metaphysical cosmologists, argue that extraplanar weak points have nothing to do with planar geometry. Instead, they have to do with energy flows. Planar dualists often speak of the metaphor of the sea of magic and the sky of Soulstuff, forming the floor and ceiling of the multiverse. In this model, extraplanar weak points represent energy currents, akin to the “rivers” of Ley Lines, that flow between planes, and are thus best thought of like a metal poker that becomes hot along its entire length when left in the fire too long. Each extraplanar weak point represents the Material Plane terminus of the metal poker, the far end sitting in the furnace of another plane.

While a full catalog of extraplanar weak points does not exist, some notable and important ones include:
- Near Tokra, in the Dunmari Basin, a pair of weak points have existed for time immemorial. One, south of the city, connects to Arborea. The other, north of the city, connects to Pandemonium
- In the lizardfolk jungle realm of Orekatu, there is place known as the Footprint of the Gods, where supposedly the separation of the planes during the Riving was incomplete, and the elemental energy of the Energy Realms leaks into the material plane.
- At the old Drankorian ruin known as the Elemental Forge, on the Freccilia River in Cymea, an extraplanar weak point to the Energy Realms was maintained by a bound elemental creature known as Sh’shethis, until the bonds were broken and the creature freed by the Dunmar Fellowship in DR 1749.
- Somewhere in the mountains south of Cedrano, there are rumors of an extraplanar weak point connected to some kind of Shadowfolds domain, or possibly the hypothesized Negative Energy Plane, associated somehow with the War of the Dark Rift.

In the Dunmar Frontier campaign, extraplanar weak points have included:
- Seemingly permanent places where a specific other plane is for unknown reasons “close” to the Material Plane. These, at least as far as is known, have always existed and cannot be straightforwardly destroyed. Examples include the links to Arborea and Pandemonium near Tokra.
- Seemingly permanent places where a planar group is drawn close to the Material Plane. Example: the Footprint of the Gods, which was canonically a place where the four major elemental planes all were “close” to the Material Plane.
- Temporary places created by some kind of strong magic, potentially requiring some kind of powerful piece of another plane as an anchor. Example: the Elemental Forge, which was created during the Drankorian Era by, presumably, binding a powerful entity from the Elemental Plane of Air, drawing elemental energy close to the Material Plane somehow. This extraplanar weak spot was canonically destroyed when the bound creature was freed. Left unresolved is exactly how binding an creature of the Plane of Air was able to draw all four elemental energies.

While the metaphysics of extraplanar weak points are left intentionally vague, so as to allow invention along a variety of different lines, there are a few key implications and canonical facts:
- Extraplanar weak points can draw a single plane, or a related group of planes. Exactly how and why is not determined. It is not canonically the case that connections to the outer planes are always singular and connections to the elemental planes are always joint, though. Any sensible combination is possible.
- Extraplanar weak points should probably never involve fundamental planes (Astral, Ethereal, etc). Ley Lines are a special case of “extraplanar weak point like things” connecting to the Plane of Magic. Whether there is anything specially connected to the Plane of Creation (akin to Ley Lines) is left undetermined, but the answer is probably no, since souls already kind of serve this purpose. Of course special cases, like the “divine ley lines” on the Circular Island, can always exist.
- Both temporary and permanent extraplanar weak points are possible, but in general these should not be things PCs can create (e.g., it takes 10 high level wizards conducting a month-long ritual or something). Most temporary extraplanar weak points intentionally created by natives of the material plane should be old, created during Drankor or before, or involve the use of ancient artifacts/scrolls/magic (e.g., Pandemonium Scroll).
- Canonically, extraplanar weak points make creating magic items much easier. The details have always been intentionally vague but this is a common reason to seek out extraplanar weak points.

A few not-quite-canonical notes:
- Extraplanar weak points shouldn’t make planar travel easier. These are not closed portals - the planar dualists metaphor gets the vibe right. Notably, this makes them very distinct from fey gates or other kinds of “fey areas” where people sometimes vanish into the feywild. These are probably something unique, more akin to elemental vortexes than extraplanar weak points (I think Ishara Venn is probably wrong as elemental vortexes allow travel, and extraplanar weak points don’t). See Planar Connections for more.
- Extraplanar weak points should make the nearby area kind of like in some ways the plane they are connected to. They should generally be dangerous, although there can be exceptions.