Material Plane

The Material Plane, or sometimes Prime Material Plane, is the plane of existence in which the world of Exandria exists.

Exandria
Exandria is the world on which most events of Critical Role take place.

Satellites
Exandria has two moons:
 * Catha: close to Exandria and appears large in the sky. It has a 33-day cycle during which it waxes and wanes.
 * Ruidus: the reddish-purple, maroon-brown color moon. It takes either half a year or approximately one full year (328 days) to complete a rotation and thus is only visible in the sky for half the year.

Other worlds
As of 836 PD, only the most expert astronomers of Exandria have learned that there are numerous worlds on the Material Plane.

Relationship to other planes
In some places, the barriers between the Material Plane and other planes become thin or are simply punched through. Some rifts are stable for long periods: there are settlements around long-lasting rifts with the Elemental Planes, and known portals to the Feywild, for example. The barriers regularly become thinner during the annual solstices: Winter's Crest and the Zenith. The barriers become especially thin under a celestial solstice.

Once opened, rifts can be widened or they can be sealed. Long-term doorways can be established between planes and realms, starting with anchor glyphs and building a permanent enchantment around them, similar to building a permanent teleportation circle.

The Immensus Gate, located in Aeor, is one of the larger waypoints between the planes. It is a large device capable of creating a portal into other Planes of Existence, with the use of a tuning fork.

Other Prime Material Planes
Artagan says, "This is but one of many Prime Materials", and suggests that he and Jester could travel easily between them.

Feywild
The Feywild, also called the Fey Realm or Plane of Faerie, overlaps the Material Plane. There are many points of crossing; Vox Machina knew of one in the Frostweald, and they created a special door allowing Artagan to return to the Material Plane. Fearne Calloway later used that gate, located in the Verdant Expanse, to travel from the Feywild to Tal'Dorei. The elven city of Syngorn has threshold crests placed around the perimeter of the city that are anchored to the Feywild, allowing the whole city to teleport to the Fey plane in times of danger.

Shadowfell
The Shadowfell, or Plane of Shadow, also overlaps the Material Plane. The only known portals are the three magic siphons that were set up throughout Exandria. The city of Thar Amphala, using threshold crests like those of Syngorn, was able to teleport to the Material Plane.

Ethereal Plane
The Ethereal Plane overlaps the Material Plane, but they are somewhat out of phase with each other.

There are several spells, items, and even innate abilities allowing creatures on the Material Plane to interact with the Ethereal Plane. Creatures who use the drug skein can see into the Ethereal Plane out to ten feet; the spell True Seeing allows the target to see 120 feet. Creatures slathered in oil of etherealness enter the Ethereal Plane for an hour. The spell Blink allows the caster to enter the Ethereal Plane for short periods and move up to 10 feet to a different position in the Material Plane; a phase spider or an incubus can switch between the Material Plane and Ethereal Plane at will.

The Elemental Planes
The Elemental Planes intersect with the Material Plane. The druidic Ashari guard most of the portals at the connecting points. Some believe the Elemental Planes were created when the Protean Gods thrust the elemental chaos from the Material Plane, but others believe the chaos simply poured through rifts from the existing Elemental Planes into the Material Plane.
 * Elemental Plane of Fire connects to Exandria in multiple locations.
 * Pyrah guards the "Rift of Flame" in the Sunderpeak Mountains. Thordak was sealed in the elemental plane, but broke back into the Material Plane through this rift on Winter's Crest with the help of Raishan. Episode-46-Coral-Helps-Seal-Fire-Rift-by-Thomas-Brin.jpg
 * Following his escape, Thordak unaccountably attacked Serpent's Head, a village in the Cliffkeep Mountains, and in the wake of the attack small rifts to the elemental plane occasionally started opening in the area.
 * Experts suspect Everplume, near the Torrid Reef south of the Shearing Channel, may contain another rift to the fire plane.
 * Elemental Plane of Water connects to Exandria through the portal at Vesrah, at Rumblecusp's Heaven Falls, and at the Cauldron Sea in Blightshore.
 * Elemental Plane of Air in Zephrah
 * Elemental Plane of Earth in Terrah
 * Frostfell in the Frostweald. Errevon the Rimelord opened a larger rift on a celestial solstice; years later, after Errevon's forces were pushed back through the rift, the Ashari sealed it.

Astral Plane
The Astral Plane, or Astral Sea, separates the material world from the Outer Planes and beyond, and had to be traversed by specially built vessels before the discovery of spells like plane shift. The Astral Plane, or Astral Sea, contains gateways to other planes and is home to the githyanki.
 * According to Lady Allura, when a Bag of Holding is destroyed, its contents are jettisoned into the Astral Sea.
 * When Scanlan Shorthalt scried through his magical poo, his consciousness transcended the Material Plane, traveled across the Astral Sea, and arrived at his scrying destination on the Material Plane.

The Divine Gate and the Outer Planes
At the end of the Calamity, the Prime Deities erected the Divine Gate, a sort of lattice through which gods cannot pass, between the Prime Material Plane and the rest of creation. Most people call this event the Divergence, though some more religious folk call it "The Penance" while students of the arcane call it "The Second Spark."

The Divine Gate has been narrated as a visible phenomenon while shifting between Exandria and several other planes, including the Astral Plane but mostly the Outer Planes: the Nine Hells, Elysium, Ioun's secret realm, and Pandemonium. The Gate seems to be most visible (at least to mortals) between the Inner Planes and the Outer Planes. It has not appeared when traveling from the Material Plane to the Feywild or to the Shadowfell, perhaps because, while the Feywild and the Shadowfell border closest to the Prime Material Plane, there is still a fine veil in between based on the Divine Gate. Nor did Vox Machina and the Mighty Nein see the Gate when traveling between the Material Plane and the Elemental Plane of Fire. The Divine Gate also does not seem to stop a god from traveling between the Outer Planes.

A unanimous effort of the Prime Deities or possibly an unsealed Tharizdun could break the Divine Gate, which would lead to another Armageddon in the mortal realm.

The Abyss
The Abyss is the home of demons like Yenk the goristro and demon lords like Yeenoghu.
 * In D&D: Dungeon Master's Guide, the Abyss is one of the Outer Planes. It "has a seemingly endless number of layers" and is associated with the chaotic evil alignment. That cosmology may not be exactly canonical for Critical Role, but the Endless Maze from which Yenk hails corresponds to a canon layer of the Abyss, as does Orcus's realm of Thanatos. Black Gate of Bazzoxan by Miloš Radojkić.jpg
 * Since the Calamity corrupted the Miskath Strand, the Cauldron Sea has some connection to the Abyss in addition to having aspects of the Elemental Plane of Water.
 * Arcane devices called "Abyssal anchors" can slowly tear holes through the barriers between the Abyss and the Prime Material Plane; they were used during the Calamity to allow demon generals to invade various places in Exandria, and the Angel of Irons cult used crude versions to cause demonic incursions in the Kryn Dynasty.
 * Around 795 PD, a group of dungeoneers accidentally reactivated a gateway to the Abyss within Bazzoxan, which has remained open ever since, requiring a full-time containment effort by the Aurora Watch.
 * Six "shackle fanes", including one hidden beneath the Chantry of the Dawn on the Material Plane, have kept Tharizdun sealed in the depths of the Abyss since the Calamity. The Angel of Irons cult used an Abyssal anchor to prepare to break the fane at the Chantry.

The Far Realm
The Far Realm is another dimension that connects to the Material Plane in some places, often in the depths of the Underdark. Aberrations from this realm may have been called to the Material Plane by Tharizdun, or may have crossed over through rifts opened by the vast forces released in the Calamity.
 * Clarota told Vox Machina that, should they try to enter through the rift to the Far Realm that they found while in the Underdark, their minds would break.