Master Assassin

The title of Master Assassin was one of the highest obtainable ranks within the Assassin Order, and those who held this title were presumed to have reached the peak of their training as an Assassin. The rank garnered a large amount of respect from other members within the Order and indicated individuals who possessed uncommon skill and talent, most often in the arts of stealth and assassination.

A Master Assassin was meant to embody the Creed: they never harmed an innocent, always hid in plain sight, and never compromised the Brotherhood.

History
In 1176, Umar Ibn-La'Ahad and his fellow Assassin Faheem Al-Sayf held the title of Master Assassin. However, Umar gave his life to spare the Brotherhood from a siege, in retribution for an assassination gone wrong.

In 1191, Altaïr Ibn-La'Ahad held the position, before being demoted to a novice following his failure to obtain the Apple of Eden beneath Solomon's Temple, along with his arrogance and disregard of the tenets of the Creed. He eventually regained this title through several assassinations in support of the Order's interests, and held it during the assassinations of Robert de Sable and Rashid ad-Din Sinan. Eventually he became Mentor of the Levantine Assassins.

In 1499, Ezio Auditore da Firenze obtained the rank, before rising to be the Mentor of the Italian Assassins, following the liberation of Rome from the House of Borgia's grasp. Also, during the 16th century, Yusuf Tazim, the leader of the Constantinople Assassins Guild, alongside the famed Turkish navy admiral, cartographer, and bomb specialist Piri Reis, were Master Assassins. As well as those two, Dogan and Kasim, who were Yusuf's lieutenants, also held the rank of Master Assassin.

In the 18th century, Achilles Davenport was a Master Assassin of the Colonial Brotherhood. Following the near complete collapse of the branch in 1763, Achilles removed himself from the Assassin affairs, but eventually returned to prominence as the Mentor of the Assassin Ratonhnhaké:ton. Ratonhnhaké:ton himself obtained the rank at some point later in his life.

By 1690, Maréchal was a Master Assassin of the French Brotherhood. By the mid-18th century, the French branch was led by a Council, which consisted of four Master Assassins: Pierre Bellec, Sophie Trenet, Guillaume Beylier and Hervé Quemar, with the Mentor Mirabeau presiding over them. Arno Dorian, another notable member of the French Brotherhood, eventually also attained the rank of Master Assassin after being reinstated.

During the period between the 19th and 20th centuries, Nikolai Orelov, a member of the Narodnaya Volya sect of the Russian Assassins, was a Master Assassin.

Middle Ages
Like other Assassins, most Master Assassins possessed the eagle beak-like design upon their hoods, but their robes were generally longer, forming a bird-like "tail" that fluttered whenever they were in an area of strong wind. In addition, their leather belts were larger, their red sashes wider and longer, and they had permission to carry any weapon they desired.

Renaissance
With the order much less public, a uniform guideline as to the attire of a Master Assassin no longer existed. The Master Assassins of the Renaissance were a small, underground group, with broader access to knowledge and weapons. Most retained their freerunning, Hidden Blades and hooded traditions. Master Assassins were also the only Assassins permitted to wield dual Hidden Blades, and in the case of the Turkish Assassin Brotherhood, hookblades.

As Assassin Dens were erected within Constantinople, Ezio Auditore promoted several high-ranking Assassins to be Master Assassins who guarded the structures. These new Master Assassins would be trained specially by Ezio to be able to fulfill their role, and this extra training allowed them to hold the Dens against Templar attacks.

Trivia

 * Ironically, despite being Master Assassins, Thomas de Carneillon and Arno Dorian never wielded dual Hidden Blades, although they could perform dual assassinations with only one Hidden Blade.
 * During Ezio's stay in Constantinople, very few Master Assassins were permitted to wield hookblades, as these were a better version of the dual Hidden Blade.