Signature weapon
A signature weapon (or trademark weapon or weapon of choice) is one commonly identified with a certain group or, in the case of literature, epic poems, comics, and film, where it is a popular trope, for both protagonist and antagonists to be associated with and highly proficient in the use of specific weaponry. An example is Robin Hood's longbow.
Signature weapons enable viewers and readers to easily distinguish between characters who are often nearly identical in appearance (e.g., the Teenage Mutant Ninja Turtles). Signature weapons are a common feature of role-playing games and video games. The acquisition of the signature weapons usually marks a newly heightened level of martial prowess and/or aids in the creation of a unique avatar.