Master Assassin's Knuckles

The Master Assassin's Knuckles were brass knuckles obtained by Jacob and Evie Frye during the nineteenth century. These brass knuckles, adorned with the Assassin insignia, were only to be used by Master Assassins. The Frye twins could craft this weapon, allowing them to use it in combat.

Reference

 * Assassin's Creed: Syndicate