Cindergrove

The Cindergrove is a forest in a caldera of a volcanic mountain, containing Pyrah, a druidic village of Fire Ashari, who guard the Rift of Flame, leading to the Elemental Plane of Fire.

Forest
Cindergrove is a forest of trees that are long leafless, dead, hardened, and petrified. Most of the wood is either gray or black from being charred. On the floor of the forest are piles of burnt-away brush and ash.

On the outskirts of the Cindergrove there is a small village called Pyrah. The village was mostly constructed from the materials people could scavenge in this inhospitable area.

Cleft
In the center of the forest, there is a large crevasse bisecting the center of the forest, about 40 feet across and about five feet wide, filled with slowly roiling lava. The air around it is substantially warped by the intense heat surrounding the lava pool, and all the trees that are right near it are all bent and have been heavily burnt.

Also nearby the cleft, there is a single stone obelisk that rises out of the ground about 15 feet up. Towards the top, it has an embedded "fist- or heart-sized" ruby, emitting small amounts of light.

Portal to the fire plane
To enter the fire plane through this portal in the Cindergrove, one must ask permission from the mountain. Once the permission is granted the lava will begin to grow exponentially active, sending off little spittles of rock. The lava will begin to slowly spin with a strange sucking sound, almost like sludge is being pulled through a tube. With a final shift of the ground and cracks from trees, bits of broken branchs and trees will fall and hit the ground, and the lava will pull down into a vortex of molten rock sinking down the crevasse, 20 feet below. The portal can now be entered by attempting a leap of faith.

To complete her third trial of her Aramenté, Keyleth has to go into the Elemental Plane of Fire to find a stone spire. After asking permission of the mountain the portal opens before her. Without hesitation Keyleth jumps in, after casting Protection from Energy on herself. Vox Machina all jump after her into the portal.

After Thordak escaped from the fire plane though the portal the Cindergrove was left in ruins. The Cindergrove is but a fraction of what it once was, most of the trees thrown hundreds of feet from the center and scattered amongst the top of the once-volcanic mountain. The mountain has been blown apart in areas, sections of large black stone have been pushed up into jagged obelisks, pits of molten rock that have been punched through the floor and have gathered into the pools of lava.