Vampire: The MasqueradeEdit
Modern Istanbul is a Camarilla city nominally under the control of Prince Mustafa, who was Embraced for the specific purpose of ruling the city. The true power, however, rests in the hands of the Toreador. The late Methuselah Vashtai used to have a major influence on the prince until her Final Death, and her childe Nakshidil has followed in her sire's steps. They keep the peace within the city, allowing vampires of all Clans within the city as long as they adhere to the Traditions. The Nosferatu entertain a vast Warren that dates back to Roman times, while even Sabbat clans like the Tzimisce are tolerated within the confines of the city. During the time of the Tremere Blood Curse, most Camarilla officials used Istanbul to meet with representatives of Clan Assamite to negotiate over contracts. With the end of the Blood Curse and the Schism, numerous Assamites have fled to Istanbul and beyond to seek protection and admission into the Camarilla. The Followers of Set are especially persistent, resisting any attempts of Nakshidil to remove them. The D'habi Revenant family is known to have a single estate within the city, while the Kairouan Brotherhood has made inroads.
Few realize who is the true power in Istanbul. Beneath the city sleeps Mahatma, a Cappadocian Methuselah that was already involved in the city before its proper foundation, and who is nominally aligned with the Inconnu. Now searching for Golconda, Mahatma silently guides the Cainite population of the city through proxies. He uses his formidable network of spies and other agents to silently dispose of any vampires he finds disruptive, while advising those he supports through dreams.
Werewolf: The ApocalypseEdit
The Glass Walkers used to have a Caern in the city that they shared with the Bone Gnawers, but it collapsed ages ago, befouled through the cities numerous bloody losses. Modern Istanbul is under dominion of the Silver Fangs of House Wise Heart. Most Garou use the city as a port to travel to the much more contested Balkans.) As with most major cities, Ratkin have constructed colonies for their broods. Pentex has one of its headquarters in the Middle East within Istanbul.
Mage: the AscensionEdit
As an important frontier city, mages had always a strong presence in the area. The Order of Hermes has a chantry that stretches back to the Dark Ages. The Celestial Chorus has its own congregation within the city, which is run in a much more egalitarian manner than its sister-congregation in Rome. Arx Karagoz, the prime Chantry of the Golden Chalice of the Euthanatoi, lies in the suburbs of Istanbul and is secretly shared with the Ahl-i-Batin. The Euthanatoi remember the Batini and try to keep their respectful distance from them when possible. Despite this, there are always numerous initiates present in and around the city, either as postulants of the Golden Chalice or as tourists who seek to visit the ruins of Troy.  The Hagia Sophia acts as the primary Node for Balador, one of the largest Chantries of the Cult of Ecstasy. The Chantry also has an earthly aspect near the museum.
The Technocracy strengthened their hold after the fall of the Ottoman Empire and their alliance with the Mokteshaf Al Nour, using the city as an inroad into the larger Middle East with its untamed local paradigms.
Wraith: The OblivionEdit
The Necropolis of Istanbul is under the dominion of the Hierarchy. Since its founding as Byzanz, the Necropolis was often assaulted by Spectres, but never fell. Acting as the central hub of Stygia for operations in Russia and the Middle East, the city is home to various Citadels, who are locked into an interdependent security system to avoid rebellion. 
As a result, revolts like the Night of Short Chains did not really affect them, making them Loyalists to Charon. The city's secure status made the it vital important for strikes against Spectre activity during the Great Maelstroms, acting as a command center in the war against Coldheart and his troops. An outbreak of plasmics known as "tin ants", who are known to dominate Shadows via a Hive-Mind like ability, added additional security to the city, as it made infiltration from Spectres near impossible.
Changeling: The DreamingEdit
Hunter: The ReckoningEdit
While the Arcanum has long held a presence in the city, they have not yet come together to form a chapter-house due to legal reasons. Currently, it is a colony of individual agents. The Imbued in the area are organized in separate cells, with one of the more prominent being the cult of Jennifer Vidasania, which preaches the coming Apocalypse and seeks to prepare its adherents to fight against the monsters in their midst.
Mummy: The ResurrectionEdit
Istanbul is connected to the Web of Faith, and during its long history numerous Reborn chose to use the city as a temporary residence, among them Horus himself. Many of the newly formed Amenti visit the city in order to study its ancient relics. The cult of the Amkhat has infested the city, spreading their dark rites to serve their master Apophis.
Demon: The FallenEdit
For the actual city, see Istanbul.