The Cut

15 feet wide at its base, and approximately the same in length, although it narrows to five feet wide (and covered) at the entrance to the tomb of Queen Eimhear. There stands a single flat slab of worked stone in an inclined groove cut into the mountain itself, a ton or more of sense gray stone. Someone has punched through the slab in the upper right corner, and begun to push the slab in its track to the left several inches.

The Tomb

Past the inclined slab that seals the entrance is the tomb of Queen Eimhear. The chamber is approximately circular, a rough-hewn 25 feet in diameter. There are exits to the east (the entrance), and two narrow passages on the western wall. There are shadowed alcoves on the north and south walls, a jumble of metallic debris half the height of a man between the two passages to the west, and primitive murals cover the four curving expanses of wall between the wall features.

The Great Seal

In the exact center of the chamber, a circle has been engraved in the floor. Into the indentation, a white metal has been hammered flush with the floor. The circle is between seven and ten feet in diameter, and is surrounded by the angular draconic script of the necromancers.

Any Bard, Wizard, or Cleric will immediately recognize this as a Place of Power, and Detect Magic reveals walls of arcene power, focused inwards.

The Murals

“There are four massive floor to ceiling murals on the tomb walls, gently curving ten to twelve feet in width. Three are primitive cave art, depicting battles and events in what is now lost to mythology; the alliance of the Cymru people and the Fair Folk in rising up against the dragon blooded Enemy. The fourth is a surreal landscape of the nearby Devils Beacon mountains, painted in a much different style.”

The Mechanism

A collection of metallic debris sits untidily on the western wall, between two passages exiting the chamber. Mostly patinaed bronze, with copper and tin hardware for good measure. The most intact piece is a round concave disc several feet in diameter; there are various other brackets as well as flat and curved lengths of metal. The whole pile seems messily deconstructed, rather than aged into structural failure. An imperial artificer or dwarven engineer could tell you more; someone in the Ingeniātor class could tell you about the subtle magics in play here (including their purpose).

The Alcoves

Narrow alcoves approximately one stride deep are inset into the curving expanses of the northern and southern chamber walls. Collapsed near each is a dessicated corpse outfitted with spear, shield, and helm; both have been hacked to pieces.

The Narrow Passages

Fine tapestries may have decorated the twin exits to the chamber in antiquity, but all that remain now are rags. Both passages widen into singular rooms with no other apparent exits. Filling the majority of space in each, an engraved stone bier decorated in nature motifs; these funeral effigies are approximately large enough for an adult Cymru to be entombed within.

Closer examination reveals toolmarks and damage to the stone lids.

The Secret Chamber

Maybe three places in length and width, the secret chamber is sunk deeper into the stone of the mountain than the central tomb area itself. Inside, a simple stone throne; and upon it the despoiled corpse of Queen Eimhear sits slumped, obviously stolen of her riches. In narrow wall alcoves are two Cymru cult statues; one representing Ceridwen (the moon goddess of wisdom), one representing Gwynn ap Nudd (the lord of the hunt).

Notes:

1. The Barrow of Queen Eimear is not, in a technical sense, actually a barrow as there is no artificial mound above it, just a mostly natural mountain range (The Devils Beacons)