Hookblade

"The hookblade helps you get around fast, surprise guards, and is not too bad in a fight."

- Yusuf Tazim.

The Hookblade was a modification to the hidden blade adopted by the Assassins Guild of Constantinople.

When Grand Master Ezio Auditore arrived in the city, Yusuf Tazim introduced this advancement to him; whereupon he also began to use it in both battle and travel.

Use
The hookblade was designed to make travel quick and easy, and was used in conjunction with ziplines planted throughout the city. It could also be used in several acrobatic movements, such as for flipping over enemies to avoid a fight, or swinging up vertical surfaces.

It could also be used with corner Chase-Breakers, where the swinging support could be used as a trapeze to reach the next rooftop, instead of going around the corner.

The hookblade could also be used as a weapon in combat, wherein Ezio pulled targets in for a close-range attack, threw an enemy onto the ground, or countered a weapon.

Trivia

 * According to the June 2011 edition of GameInformer, Assassin's Creed: Revelations will feature a new control system. Pressing the "Empty Hand" button (O on the PS3, Shift on the PC, and B on the Xbox 360) will now trigger the hookblade.
 * It is stated by the developers that the hookblade should increase navigation speed by 30%.
 * The actual hook of the hookblade resembles the head of an eagle, a bird frequently associated with the Assassin Order.
 * Unlike the hidden gun and poison blade, the hookblade is an upgrade for Ezio's secondary hidden blade, rather than his primary one.