The Elemental Plane of Fire
Everything is alight on the Elemental Plane of Fire. The ground is nothing more than great, evershifting plates of compressed flame. The air ripples with the heat of continual firestorms, and the most common liquid is magma, not water. The oceans are made of liquid flame, and the mountains ooze with molten lava.
It is a crematorium for the unprepared traveler and an uncomfortable spot even for the dedicated adventurer. Fire survives here without need for fuel or air to burn, but flammables brought onto the plane are consumed readily. The elemental fires seem to feed on each other to produce a continually burning landscape. The City of Brass, the domain of Kyrion, the Primarch of Fire, is also located within this plane.
Vortices to the Plane of Fire can often be found in pools of molten lava or the upwelling of magma in active volcanoes.
Arriving on the Plane of Fire is like stepping into the flaming maw of an ancient red dragon; if one doesn't have protection or immunity from temperatures high enough to melt stone then death is swift. The following discussion assumes a visitor and all their clothing and gear have this capability and either do not need to breathe or can compensate for a superheated, often toxic atmosphere that can immolate one from the inside.
The dangers of the plane cannot be overstated, but those that survive the trip see wonders and beauty at nearly every turn. Flame colors span the rainbow, from the vermilion of a forge hearth to the yellow-white of heated iron, from the blues and greens of alchemical reactions to the familiar candle-flame yellows and oranges. The conflagration forms fountains, jets, sheets, rivers, waves, walls, rains, cascades, clouds, swirls, and pits of brilliant incandescence on a scale found nowhere else.
Unlike the other three elemental planes, the Plane of Fire has normal gravity and a landscape, although most of the "ground" is made primarily of loosely packed elemental fire and feels like walking in a swamp of hot coals.
Visibility is hampered by the smoke coming off the flames engulfing, but not consuming, nearly every solid, liquid, or gas (and creature) on the plane. What one can see is usually distorted by heat ripples. Geographic features such as hills, mountains, and cliffs do not have a geologic lifespan because even the more solid areas slowly move like a subterranean magma flow as seen on the Prime Material Plane.
Elementals are sentient pieces of the plane itself, moving with something that resembles volition and purpose. They include elemental analogs of creatures of the Material Plane, as well as the fire elementals. Such elementals normally have no love of fleshy, cooler creatures, and many attack merely to burn them and feed off the flames. The native language of most inhabitants of the Elemental plane of Fire is Ignan, a sharp, hissing and clicking language.