Elemental

Elemental refers to both a type of creature, and to the specific incarnations of the four classical elements: air, earth, fire, and water.

General characteristics
Elementals are manifestations of an element. The Monster Manual, 5th Edition, which may not be canon for Critical Role, notes that on their home planes, elementals are formless spirits unless focused by magic, and they are analogous to animals on the Material Plane in their motivations and sentience. All are immune to poison, resistant to physical damage from nonmagical sources; and cannot be exhausted, paralyzed, petrified, or knocked unconscious.

Types of elemental
Air
 * Djinni: The genies of elemental air.
 * Invisible stalker
 * Air elemental: Air elementals have a tornado or whirlwind-like appearance, with a barely-perceptible face.
 * Lightning spirit
 * Storm spirit

Earth
 * Earth elemental titans
 * Dao: The genies of elemental earth.
 * Earth elemental: Earth elementals have a vaguely humanoid shape, but are made of dirt and stone.

Fire
 * Phoenix
 * Efreeti: The genies of elemental fire.
 * Cinderslag elemental
 * Fire elemental: Fire elementals set their surroundings alight, and can be stopped with water.
 * Salamander
 * Azer
 * Fire snake
 * Magmin
 * Wildfire spirit: Elemental familiars summoned by Circle of Wildfire druids.
 * Thordak's spawn were primal elemental dragons.

Water
 * "Elemental leviathan"
 * Marid: The genies of elemental water.
 * Water elemental: Water elementals are shaped like tidal waves and can engulf their foes.

Mixed elements
 * Dust Titan
 * Frost salamander
 * Dust mephit
 * Ice mephit
 * Magma mephit
 * Smoke mephit
 * Steam mephit

Related race
One of the origins of genasi is as descendants of the genies of various elements: air genasi descended from djinn, earth genasi from dao, fire genasi from the efreet, and water genasi from marids.

Pre-stream
Elemental titans were involved in the battle between prime deities and betrayer gods, supported by the latter. Eventually, they were defeated and locked away in the elemental plane. Only small rifts remain between the main plain the titans'. The Ashari make it their duty to guard them, ensuring that nothing dangerous can pass through.

Campaign one: Vox Machina
As a Circle of the Moon druid, Keyleth could wildshape into elemental form, and often did so in combat. Vox Machina encountered elemental foes several times, notably fire elementals at the portal to the Elemental Plane of Fire in Pyrah, and water elementals as they approached Vesrah. Keyleth's Spire of Conflux also had the capacity to conjure elementals.

Campaign Two: The Mighty Nein
The Mighty Nein also faced elementals in the fight in which they freed Xundi, and fought them several times in Eiselcross. Beau had an elemental gem looted from the Sour Nest which permitted her to summon a fire elemental, which she did against Thelashas.

Notable elementals

 * The Primordials
 * The Molten Titan whose death created the Daggerbay Mountains
 * The earth titan whose death created the Zenwick Mountains, in whose body Thomara was built, and which Vecna animated to attack Vasselheim.
 * The Dust Titan encountered in Pandemonium by Vox Machina in
 * Errevon the Rimelord, who invaded the new realm of Tal'Dorei, bringing about the Icelost Years
 * Marrake al-Sidan al-Hariq ben Lazen, Grand Sultan of the City of Brass
 * Khedive Xundi, a marid whose home is the Silver Silt Palace in the Elemental Plane of Water but who was enslaved for the benefit of Nicodranas
 * Little Mister, a wildfire spirit that takes the form of a monkey, who bonded to the faun Fearne Calloway