Valley of Mirrors

The Valley of Mirrors is a strip of land stretching from northeast to southwest near the northern end of Lunash, the largest island of The Crescent. It is barely a half a dozen miles across at its ends and bulges to no more than four times that along its 100 mile length. This secluded and fertile valley is protected by a hidden entrance somewhere between the steppes of the surrounding region. It is subject to seasonal lightning storms and sheets of mica often scar the valley floor. These are created when lightning strikes fuse the sandy soil below. This reflective layer can become large in area but it is also very thin. It usually doesn't survive long against the prevailing winds and blowing sands. However, for as long as they last, the patches of mica reflect the sun's rays, thereby giving this place its name.
The Firefly Elm Oasis lies along the northern edge of the valley. It gets its name from the mating ritual of the fireflies native to the region. At summer's peak, the fireflies all gather in the grove of elm trees at the heart of the oasis to mate. Residents of the valley even say that the fireflies gather at one specific, ancient elm. This gathering is quite spectacular for those lucky enough to see it but the constantly changing landscape and dangerous storms makes the oasis hard to get to even for the most talented navigators.
The humanoid residents of the valley are all fehlar; members of a handful of clans all belonging to the same tribe. The shifting landscape and harsh weather of the valley have forced these into nomadism. The fehlar of the Firefly Elm Oasis don't stay in one place for too long. Their lifestyle does have the benefit of making for a strong defense of their valley against occasional intruders. Of these, goblins raiders from the mountains to the north are most common. The fehlar deal with these by constantly moving around, leading them around the valley in circles and using the mirrored landscape to disorient them. Eventually, the invaders are depleted of their resources and any survivors are stranded.
The valley also gets occasional visitors of more passive natures, but these are rare. Most common among these are other fehlar from elsewhere on the Crescent and their dwarven neighbors. Human, elven, and visitors of other ancestries are exceptionally rare but their frequency has increased since the Horde Wars. Rare as these visitors may be, when they come, they also pose a great threat to the valley's people but one of a very different sort. The natural curiosity of the fehlar combined with the stories of the delights and wonders of the outside world means that many of the valley's residents leave for the outside. They do often return later in life but the exodus has intensified in the decade or more since the great wars and some fear a coming crisis will result.