Planar Breaches

If you can’t go to the planes, don’t worry; sometimes they come to you. The divisions between different planes of existence are usually unassailable. But in a multiverse where magic, psionics, and divine decree daily wrench reality into unnatural configurations, that which separates one space from the next can wear thin. That’s when the phenomenon known as planar breaching occurs.

Planar breaches can be minor, severe, or complete. Minor breaching is often overlooked because its effects are not immediately obvious, while at the other end of the spectrum, a complete breach opens a hole in reality where laws and planar natives mix in the middle.

Wily planar travelers sometimes use severe and complete planar breaches to get around, though unless they are responsible for causing the breach in the first place, it’s hard to count on such phenomena (except, of course, for locations such as the Breaching Obelisk, a planar touchstone location described in this chapter).

Dungeon Masters may use the following definitions to guide the creation and execution of a planar breach. A planar breach has an onset, an area, a severity, and a duration.

Onset: Most planar breaches come into being over the course of 1d4 rounds. The occurrence of a planar breach is accompanied by discharges of visible light, an atmospheric disturbance that causes a wind, and a basso rumbling.

Area: A breach, regardless of its severity, affects an area 10d10 feet in radius.

Severity: A breach can be minor, severe, or complete. For minor or severe breaches, one plane is called the breaching plane, and the other is called the destination plane. Usually, only one trait from the breaching plane leaks through to the destination plane. In a complete breach, all traits from both affected planes leak equally into each other.

Minor Breach: A minor breach occurs when one alignment, elemental/energy, or magic trait described in the Dungeon Master’s Guide leaks from one plane to another. You can choose a trait or roll for one on the Random Planar Breaching table.

Elemental and energy traits in a minor breach are nowhere near full strength. If an elemental or energy trait is determined to be present in a minor breach, the overtly noticeable effect is that it is hotter (fire), windier (air), damper (water), dirtier (earth), brighter (positive), or darker (negative). Additionally, creatures with a subtype corresponding to a leaking energy trait gain a +1 bonus on attack rolls, saving throws, and skill checks. Likewise, spells that have a descriptor coresponding to the leaking energy trait receive a +1 bonus to their save DC, if applicable. All creatures inhabiting an area where positive energy leaks through heal at twice their normal rate. All creatures inhabiting an area where negative energy leaks through heal at half their normal rate. These weakened elemental and energy traits do not manifest in a severe or complete breach.

Severe Breach: A severe breach occurs when one alignment, elemental/energy, magic, or physical trait described in the Dungeon Master’s Guide leaks between one plane and another. You can either choose a trait, or roll for one on the Random Planar Breaching table.

The trait, whatever its effects, is applied across the entire area of the breach. This can be spectacular for a waterdominant or fire-dominant trait, and quite dangerous for creatures in the area. Natural structures and land forms in the breaching area can also be affected or damaged by the change in environment. For instance, an area that suddenly gains the fire-dominant elemental trait becomes a roaring area of flame that deals 3d10 points of fire damage every round to all creatures and objects within it.

A severe breach also represents such a thin boundary between planes that creatures and objects from one plane can slip or squeeze through to the other side. When a creature or object first enters an affected area on either the breaching or destination plane (or if the area comes into effect where a creature or untended object already exists), there is a 20% chance that the creature or object slips through to the other plane. A creature that wants to make this transition can increase this chance to 100% if he makes a DC 15 Knowledge (the planes) check.

Unlike with minor breaches, severe breaches require the DM to specifically determine the breaching plane in case travel occurs between the two places.

Complete Breach: When a complete breach occurs, a hole is ripped in reality. The hole is a 10-foot-radius sphere that inhabits the center of the 10d10-foot-radius area of the breach on both affected planes. This larger affected area exists on both affected planes and contains the traits of both affected planes. The hole at the center is an open portal between the planes. Creatures from either plane can move as they will through the hole.

If the planar material on one side is less dense than the material on the other, transport may occur. For instance, if the air pressure on one side is much higher than on the other, a roaring wind blows out one side of the hole, while a sucking vortex comes into being on the other (small differences in pressure create only a slight breeze). If water exists on one side and not the other, liquid jets out one side, but swirls away on the other.

Unlike with minor breaches, complete breaches require the DM to specifically determine the breaching plane in case travel occurs between the two places.

Duration: Most planar breaches last 1d6 days minus a certain number of hours. A minor breach lasts 1d6 days minus 12 hours (with a minimum duration of 12 hours), a severe breach lasts 1d6 days minus 48 hours (with a minimum duration of 1 hour), and a complete breach lasts 1d6 days minus 72 hours (with a minimum duration of 10 minutes). When the duration expires, the planar breach recedes, taking the same amount of time and causing the same atmospheric disturbances and effects as during the breach’s onset.

Breaching usually occurs randomly. Material Plane locations are less likely to see a breach; in fact, they almost never experience one. A planar site is a good candidate for a breach if it meets any of the following criteria.

• The location is home to a regular energetic event, such as a volcanic vent, an oceanic whirlpool, an evil sacrifice, and so on. A one-time event of significant proportion can also make that location a breaching candidate, such as a spectacular volcanic eruption, a whirlpool of epic proportions, a mass evil sacrifice, and so on.
• The location was used to launch a planar trip via magical or psionic means, such as by using the spells plane shift, ethereal jaunt, etherealness, astral projection, and so on.
• The DM wants a breach to occur at the location. This criterion is particularly useful in campaigns set on the planes where the average character level is deemed too low for wide-ranging exploration or adventuring. A planar breach allows the DM to inject planar material into the game without unduly endangering the player characters. Instead of having the heroes risk a journey into the Abyss, for example, a bit of the Abyss can come to them.

In addition, certain spells (such as precipitate breach), items, and locations can cause a breach whether or not an area is a candidate for a natural breach.

If the DM decides that an area is a candidate for a breach, he can arrange all the details ahead of time, especially if designing an adventure with a specific goal in mind. However, the DM also can generate a random breach, which is a good way to create seeds for a new adventure.

To generate a random breach, the DM first rolls d% to see if a breach occurs at the location. Each day, a candidate site has a 4% chance to experience a breach. Once a breach occurs, the tension is relieved, and the location is no longer a candidate for future breaches (unless the DM determines otherwise).

When a breach occurs, the DM then rolls to decide the severity of the breach.

Breach Severity

d%	Severity
01–75	Minor breach
76–93	Severe breach
94–100	Complete breach

Finally, the DM rolls on the Random Planar Breaching table to determine a trait for the breach. If the breach is minor, reroll any results that are not alignment, magic, or elemental/energy traits⁠—​only those types are allowed in a minor breach.

Table: Random Planar Breaching

d%	Trait1	Trait Type	Breaching Plane2
01–03	Air-dominant	Elemental/Energy	Elemental Plane of Air
04–06	Alterable morphic	Physical	Ethereal Plane
07–09	Chaos-aligned, mildly aligned	Alignment	Abyss
10–12	Chaos-aligned, strongly aligned	Alignment	Limbo
13–15	Dead magic	Magic	Dead magic demiplane5
16–18	Divinely morphic	Physical	Outlands
19–21	Earth-dominant	Elemental/Energy	Elemental Plane of Earth
22–24	Evil-aligned, mildly aligned	Alignment	Abyss
25–27	Evil-aligned, strongly aligned	Alignment	Hades
28–30	Fire-dominant	Elemental/Energy	Elemental Plane of Fire
31–33	Flowing time3	Physical	Slow-time demiplane5
34–36	Good-aligned, mildly aligned	Alignment	Celestia
37–39	Good-aligned, strongly aligned	Alignment	Elysium
40–42	Heavy gravity	Physical	Heavy-gravity demiplane5
43–45	Highly morphic	Physical	Limbo
46–48	Law-aligned, mildly aligned	Alignment	Nine Hells
49–51	Law-aligned, strongly aligned	Alignment	Mechanus
52–54	Light gravity	Physical	Light-gravity demiplane5
55–57	Magically morphic	Physical	Magic morphic demiplane5
58–60	Negative-dominant	Elemental/Energy	Abyss
61–63	Negative-dominant, major	Elemental/Energy	Negative Energy Plane
64–66	Neutral-aligned, mildly aligned	Alignment	Plane of Shadow
67–69	Neutral-aligned, strongly aligned	Alignment	Neutral demiplane5
70–72	No gravity	Physical	Ethereal Plane
73–75	Objective directional gravity	Physical	Pandemonium
76–78	Positive-dominant	Elemental/Energy	Ysgard
79–81	Positive-dominant, major	Elemental/Energy	Positive Energy Plane
82–84	Sentient4	Physical	Sentient demiplane4
85–87	Subjective directional gravity	Physical	Astral Plane
88–90	Timeless	Physical	Astral Plane
91–93	Water-dominant	Elemental/Energy	Elemental Plane of Water
94–100	Wild magic	Physical	Limbo
See trait descriptions on pages 147–150 of the Dungeon Master’s Guide. The breaching plane serves only as an example; the DM may choose a different breaching plane, or make up a plane or demiplanes of his own choosing to serve as the breaching plane. 1 round in breach area equals 1 year outside breach area. A sentient plane or demiplane that breaches affects the destination plane as if it is “haunted.” Objects move of their own volition, creatures in the area get a sense of “being watched”, and strange noises are heard. The DM is free to add additional effects. These demiplanes are only as large as the breach area in the destination plane and exist only as long as the breach itself exists. The DM may determine other demiplane traits or inhabitants as desired.