The Great Gate of the Uunglarda
The wall illumined by the ethereal glow of the Luxanary was not the natural sides of the cavern, but a fortification constructed with huge blocks of grey and black stone that towered upward to meet the ceiling of the cavern overhead and stretched outward to the sides of the cave. It entirely blocked the way. The cavern ceiling was formed of one solid piece of stone; like the base of a mountain resting precariously atop an empty tomb.
The floor of the chamber was laid with enormous squares of similarly hued stone and in the center of the mammoth wall before them, fashioned of heavy iron that shimmered in the phosphorescent radiance illuminating it, a massive black gate stood in the darkness.
Beyond the gate, a path strewn with rough gravel led beneath a continuation of the fortified wall, forming yet another tunnel, but where it led was concealed by impenetrable blackness. Standing in the barren cavern, the Fey of the Light stared in horror at the imposing edifice, unable to conceive how they might escape with such a massive barricade across the way.
Rearing up to a height of a dozen feet or more, the gate forged of heavy wrought iron was secured to the stone blocks of the wall on either side with enormous iron bolts. It did not open in the center and swing outward like a pair of doors. It did not open at all. It was fashioned in one piece, it's iron twisting in elaborate spirals, curling in ornate circles and fanning out like leaves.
To ensure its impassability, the ironwork of the heavy gate had razor-sharp blades forged into its spiraling rods and bars. It did not have a lock upon it that could be undone by magic. It was constructed to stand as an impenetrable barrier between the Realm of the Reviled Fey of the Uunglarda and the Free Lands under the Sovereignty of the Fey of the Light.