Plunged miles beneath the oppressive sun, carved into the floor of an endless, star-lit cavern, lies Erelhei-Cinlu, the ancient, dark heart of the Underrealm and the crown jewel of the Vault of the Drow. Under a vaulted sky of shimmering phosphorescent minerals and bioluminescent fungi, visitors to this ruthless subterranean metropolis can marvel at the soaring basalt spires of the matriarchal Noble Estates, browse exotic goods and rare poisons in the Grand Bazaars, or thrill to gladiatorial combat near towering spider-temples. Catering to those of discerning taste and dangerous ambition, Erelhei-Cinlu offers an atmosphere of unrivaled dark luxury where travelers can sample fine fungi wines, contract elite mercenaries, and seek their fortune in the shadows—provided they keep eternal vigilance, for in the twilight of the deep, you either rule or you serve.