Location from Sailor Moon by Naoko Takeuchi / Toei Animation
The organization led by Queen Beryl and powered by Queen Metalia's dark energy — headquartered at D Point in the Arctic, where the seal on Metalia is weakest.
The Dark Kingdom is what happens when the Silver Millennium falls and someone channels that collapse into a weapon. Beryl leads it. The four Shitennou execute her orders. Queen Metalia provides the power and the goal: more energy, always more energy, until she can fully revive and control the world. The seal on Metalia is located at D Point in the Arctic — Queen Serenity placed it there to contain the entity that destroyed the Moon Kingdom. Breaking the seal is the ultimate goal. The first season ends here, on ice, with Sailor Moon.
D Point in the Arctic: a landscape of ice and stone, dark energy rippling through the air, the atmosphere pressing down on anyone who enters. The Dark Kingdom's interior is appropriately theatrical — crystal spires, dark corridors, Queen Beryl's throne room with its crystal ball at the center.