This is the largest layer of Thelanis and the heart of the plane. The Moonlit Vale is essentially a country, with the feyspires spread across it as cities; it’s possible to spend days traveling from spire to spire. While it’s largely arboreal, there are beautiful valleys, glittering lakes, and a vast mountain. It’s always night here, and the moon Rhaan radiates bright light, always seeming to hang just above the viewer. While the moon doesn’t move or change, the seasons do; in winter, the court is covered in snow, while in spring, it’s in brilliant flower. This has nothing to do with the passage of time, and everything to do with the intrigues of the Palace of the Moon; the current season indicates which seasonal court is currently dominant. This is a crucial aspect of the Moonlit Vale: things change. The baronies are fixed in their stories, but the intrigues of the four seasons are the story Thelanis tells itself.
The Moonlit Vale embodies the general idea of the fey— otherworldy beauty and magic. There are many natural displays of illusion— streams of glowing mist, ethereal music, distant song. Motes of light drift slowly through the trees. The beasts of the region are sleek and graceful, and have unusual colors and patterns; while many use standard stat blocks, sentient beasts might use the statistics for Valenar beasts from Eberron: Rising from the Last War (though these aren’t in any way related to the Tairnadal). The land is fertile, game is easy to hunt, and adventurers have advantage on foraging checks . . . though hunting without permission may incur the wrath of the local fey.
The grandest city in the Moonlit Vale is the Palace of the Moon. Its towers are built into the trunks of four vast trees, each one reflecting the influence of a particular season. The Summer Tree is in full bloom, while the Winter Tree is withered and bare. The four seasons are factions among the fey of the Moon Court, and those who dwell within the palace live within the tree of their season. The palace is full of endless intrigues, and envoys negotiate alliances with the feyspires and the anchor barons. To mortals, many of these intrigues would seem trivial and strange, but for the fey, they determine the ruling season, which sets the tone for the layer. At the apex of each season—perhaps a strangely arbitrary declaration in a realm with such a casual relationship to time—the fey of the ruling season host a grand revel, which draws archfey from all throughout the plane; this is a moment when intrigues bloom and stories are shaped, a time for duels and grand declarations.
The feyspires are the cities of the Moonlit Vale. Each is home to a single archfey whose personal story is reflected by the spire, along with a few greater fey and a host of eladrin and other mortals. Many feyspires serve as planar beachheads; they are tied to specific manifest zones in Eberron, and when the time is right, they can slip into Eberron for a short time. Usually the feyspires are hidden by powerful illusions during these times, but there are stories of people stumbling into magical cities that are gone the next day. In fourth edition, the Eberron Campaign Guide explored the idea that feyspires could be trapped in Eberron following the Mourning; it’s up to a DM to decide if that’s the story they want to tell. Here are a few notable feyspires:
Pylas Pyrial is the Gate of Joy, celebrated for its bards and revels. Tied to Zilargo, it has a significant gnome population. Shae Joridal is the City of Emerald Lights; its illusionists are legendary. It appears in what is now Darguun.
Shae Loralyndar is the City of Rose and Thorn, an arboreal spire frequently found in the Twilight Demesne of the Eldeen Reaches. Many Greensingers have close ties to this city.
Shae Tirias Tolai is the City of Silver and Bone. Tied to Xen’drik, it was sacked by the giants of the Cul’sir Dominion and never reclaimed; some believe the elves of Eberron are descended from the eladrin of Shae Tirias Tolai. Today, it’s a haunted ruin, shunned by the fey.
Shaelas Tiraleth is the Court of the Silver Tree, largest of the feyspires. Its ruler, Shan Tira, is a master diviner and gifted oracle. All archfey respect her words, and she serves as a mediator between the seasons of the Moon Court. The spire is tied to Cyre, and there are stories that suggest the first Princess Cyre herself may have been a student of Shan Tira.
Taer Syraen is the Winter Citadel, seat of the Prince of Frost. This martial spire appears in a barren region of Karrnath. It’s closely allied with the winter fey of the Moon Court.