Over the next two hundred years or so, individual brotherhoods adapted their own style of Hidden Blade for their Assassins.
Their addition in Ezio's trilogy seems to have been for varied gameplay purposes, meaning they didn't have much weight on the lore, unlike the finger modification. These never became mainstays in the brotherhood, it seems, as they were quickly replaced with more viable weapons in later years. Inspired by Altair's writings, Leondaro Da Vinci also created for Ezio quite a few variations of the Hidden Blade such as the Hidden Gun and Poison Dart launcher.
