Build a massive, grim, and imposing...

Build a massive, grim, and imposing Dark Empire style castle with a grand gothic aesthetic, occupying exactly a 100 × 100 area. The design should feature sharp spires, towering fortified walls, and deep gothic arches. Utilize a color palette of deep grays, blackstone, basalt, and dark prismarine. Include ominous glowing accents using soul lanterns, sea lanterns, or redstone lamps. The castle must feature a central dark citadel, heavy iron-barred gates, oppressive battlements, and underground catacombs. Ensure the architecture feels oppressive, monumental, and architecturally complex, complete with flying buttresses and oppressive gargoyles.