Derinkuyu

Derinkuyu was a hidden city in,. Most of the city's expanse was concealed underground, with only a few skylights to let sunlight through.

After the Byzantine Templars reasserted their presence in the Ottoman Empire in 1509, they took over the city of Derinkuyu. It became their headquarters, and served as the base of operations throughout the Empire.

Templar headquarters
During the early 16th century, the Templars set up their headquarters in Derinkuyu, after having been driven from their previous base in Rome by the Italian Assassins. There, the Templars set up prisons and installed themselves as the rulers of the city, filling the streets with Byzantine Templars.

The one in charge of the Masyaf expedition, Manuel Palaiologos, resided in Derinkuyu for some time after his family lost their hold on the Ottoman throne. Manuel's forces were garrisoned in the city, and both he and his fellow Templar Shahkulu held power within its walls.

In 1511, after negotiating the purchase of firearms from Tarik Barleti, the Captain of the Janissaries, the shipment was stored in the Derinkuyu stronghold.

Assassin infiltration
By 1511, Tarik Barleti had Ottoman spies active within Derinkuyu. These spies were meant to observe the Templar activity in the city, and report it back to the Janissaries. After gaining enough information, Tarik planned to attack the Templars where they felt safest: Derinkuyu.

In March of 1512, the Assassin Ezio Auditore visited the city, following his search for the final key to Altaïr Ibn-La'Ahad's library. There, he met with one of Tarik's spies, a young woman named Dilara, who told him of the capture of all her fellow spies the previous week.

As the two parted, Ezio made his way around the city, where he overheard Byzantine Templars discussing Dilara, who they had captured just outside Derinkuyu's prison. They also spoke about Manuel's bodyguard Shahkulu, and how he was preparing to kill her and several other spies.

Unfortunately for them, neither the guards nor Shahkulu had the key to Dilara's prison cell, as it was at the city market, held by an off-duty Byzantine. Ezio tracked down the guard, and pickpocketed the key to liberate Dilara. The two then left for Derinkuyu's chapel to kill Shahkulu.

They arrived in time to see Shahkulu beating a spy named Janos. Ezio free-ran around the area and made his way to a small platform, directly above where Shahkulu stood, since he realized that the Templar's armor was too thick for bullets. Ezio leapt from the beam, and air-assassinated Shahkulu with his Hidden Blade.

Though Shahkulu fell, he reached up to strangle Ezio as the Assassin was speaking his last rites, to which Ezio responded by stabbing him once more in the shoulder, to make the man release his grip on his throat.

Unfazed, the Turkmen renegade shrugged off the second injury, and attempted to fight the Assassin alongside his guards. After a brief skirmish, Ezio finally killed Shahkulu, and questioned the two spies about the firearms Tarik had delivered to the Templars.

He realized that he could ignite the delivered gunpowder to flush out Manuel Palaiologos and, ignoring Dilara's protests that he would cause a panic in the city, Ezio left for Derinkuyu's stronghold.

Hunt for Manuel
Ezio entered Derinkuyu's depot, where their armaments were stored, and searched for the rifles. Upon finding the gunpowder, he ignited it, creating a large explosion that blazed through the stronghold. The resulting fire blazed through the wooden fortress, choking the entire city with flames and smoke.

Upon hearing the loud explosion at the weapons depot, Manuel Palailogos rushed out onto an elevated area, where he had a clear view of the entire city. From there, Manuel began calling out to the panicked citizens for calm, but he fled upon seeing Ezio advancing upon him.

As Manuel ran, he called out for his guards to kill the Assassin, and eventually made his way through a large gate in the corner of the city. He slowed upon reaching the small port at Derinkuyu's underground river, but Ezio, who had scaled the closed gate, cornered him there.

Manuel was forced to confront the Assassin, and the two met in a duel. Despite his efforts, Manuel was bested, and was subsequently killed in the confrontation. Ezio then took the final Masyaf key from Manuel, but he was confronted by Prince Ahmet on a boat offshore, who revealed himself to be a Templar as well.

Ezio conversed briefly with Ahmet, and the Ottoman prince commanded his men to kill the Assassin, before departing from the city.

City fire
The fire Ezio had caused at the stronghold spread alarmingly through the city, filling the underground chamber with smoke, and forcing an evacuation. Ezio fled with the rest of the civilians, many of whom were killed by the thick smoke, or by the falling rubble from burning buildings.

Throughout the duration of the evacuation, Derinkuyu's alarm bell rang loudly, and explosions periodically rocked the entire city. Despite the raging fire and deafening blasts, Ezio and a number of civilians managed to escape Derinkuyu, and left the city by boat.

Trivia

 * In an interview with CVG, Alexandre Amancio noted that parts of the city were reminiscent of.
 * While in the city, Ezio could neither gain nor lose Notoriety.
 * The unique items sold in Derinkuyu contained Templar taxes, which raised their prices by 10%.
 * After his first visit, Ezio could take a boat to Derinkuyu from the Eastern Galata District docks.
 * There was only one view point in the whole of Derinkuyu.