John Wick
One of the most surprising aspects about 2014’s hit action movie John Wick was the incredible amount of world building it did. Fitting more assassins into this setting would be a natural fit, as a secret underground for criminals could balance nicely with the aristocratic nature of the Templars. Even if we avoid the character John Wick entirely, it would still open up a plethora of interesting locations and themes that we sadly don’t get to explore in Assassin’s Creed.
From a gameplay perspective, this would be the most challenging as everyone uses firearms, though a case could be made that ours is one that just uses blades. It’d make the combat have to shift to a stealth focus since you don’t want to be gunned down, but combining your Hidden Blade with a few pistol rounds could make for some flashy executions. Just make sure to not kill any dogs, the last thing you want is to make John Wick mad.