The Brass Knuckles are a robotic variety of Echidnas from a future version of Mobius. They are the most numerous enemy of the Freedom Fighters of the Galaxy.
- The Freedom Fighters of the Galaxy and their enemies, including the Brass Knuckles, currently hold the fifteenth-longest non-appearance gap in the main series, though it is unknown if they will return at all (StH: #104-#207)
Their name derives from the weapon known as Brass Knuckles, which have been made illegal in a wide range of the U.S.
- Given their name, it is likely that the Brass Knuckles are intended to be descendants of Knuckles the Echidna. Their name is also shared with the hand weapons.
- Whether intentional or not, the Brass Knuckles' mechanical nature makes them resemble the Cybermen of Doctor Who-fame.
- In the Off Panel for StH #243, a version of Metal Knuckles known as Brass Knuckles is featured. However, this version bears little resemblance to the Mobius Galaxy villains.