The Court of Night

The Court of Night is the only city of the vampire race, and is the ceremonial and political center of vampiric society. Created in the distant past by unknown means, it's been inhabited continuously since it was first built; it's a sacred place for a race that has little permanence in a world where they live in a state of constant deception.

Location

The Court of Night is intensely magical, and doesn't have a single fixed location. Where exactly it exists isn't entirely clear; some think that it magically moves from place to place, temporarily displacing any matter that exists in the space it jumps to, while others think that it exists somewhere in the Otherlands and its entrances are simply magical gateways. Whatever the case, its stable interior suggests a deep underground cavern of perpetual darkness. What parts of the landscape haven't been altered by construction remain natural, jagged stone; occasional disembodied pipes and wires appearing from the ceiling in places seem to support the theory that the city has some sort of physical location that's constantly changing.
Reaching the city is done via doorways that can be found hidden throughout most major Old World cities. Generally located in dark, subterranean, and out-of-the-way places like subway and construction tunnels, these walled-off entryways are built in such a way to match the setting around them. They require a smear of vampiric blood to open, melting away the stone or brick that blocks the doorway and leading into the Court of Night.

Layout and Features

Loosely centered around a great chasm that bisects the cavern, the massive buildings of the Court of Night are built along various shelves of stone and up and into the walls of the cave itself. Buildings are almost exclusively for formal habitation, with no kind of commerce or industry; most major vampire clans maintain a stronghold in the city, even if they spend the vast majority of their time on the surface. It's a place for gathering, strategizing, and playing at politics, as well as a secure location where many choose to keep their wealth and private sanctums. Violence within the Court is strictly forbidden, another reason that it's an appealing option as a fallback during inter-clan conflicts.
At one end of the cavern, the chasm widens into a yawning abyss with no apparent bottom that emits mists and vapors to hang in the air. This is considered a place sacred to the Blood Gods, and the most direct place for their followers to commune with them; a jutting promontory of stone holds a sacrificial altar that's used in most major celebrations and rituals. The Blood Gods can manifest their likeness here to speak directly with their faithful, and the chasm's edge is bordered by a wide paved area with no buildings in order to let a large crowd gather there. 
On a small plateau of bare stone near the city's center, a solitary building holds the Book of Lineages, a relic of enormous religious and practical significance. Dating back to the earliest days of the vampire race and thought to predate the Blood War, it records all vampiric bloodlines and notes what god each individual vampire is claimed by. Each fledgling vampire is brought to the Court of Night to offer their blood to the Book upon their Blooding; once their blood is accepted, their entry cannot be removed from the book and will magically track them via their connection with their god.  A name turning dark is a sign of a vampire severing their connection from their patron, indicating either their death or defection to the service of the Bound One.

Population

The Court of Night has a minimal fulltime population, largely due to the fact that its inhabitants need to leave the city in order to feed. Of those who consider the Court their permanent home, most are priests or strict devotees of one of the Blood Gods. Those who live their are exclusively vampires; the Court is considered holy ground, and bringing members of the other races there is vanishingly rare. While it would be practical to keep a captive population available for feeding, it's forbidden for any non-vampire to live within the Court of Night and those who pass through are either immediately drained to the point of death or intended as sacrificial victims.
A unique aspect of the Court is that vampires here almost exclusively wear their true forms, something they do in few other places out of the need for secrecy. Assuming their more humanlike forms while in public in the Court is seen as disrespectful to the gods, and is highly frowned on; some vampires will assume their secondary form while in their own private sanctums for the sake of personal preference or for the purpose of physical intimacy, but most enjoy the opportunity to show their true selves.
Like the vampiric race as a whole, the city has no single ruler. Its primary purpose is as a gathering place during times of crisis or for religious ceremony, and during these times it's loosely governed by the heads of the most powerful clans as well as the most highly favored priests of each of the Blood Gods.