The Merchant is an enemy in Final Fantasy VI. It only appears in South Figaro during Locke's scenario, and is fought by talking to the merchants that appear around town. The Merchant is one of the few non-boss enemies in the game not to have a palette swap.
Merchants only use physical attacks and are not difficult to defeat. The true purpose for fighting the Merchants is to steal their clothing, resulting in Locke donning a Merchant uniform and being able to access certain hidden passages by speaking to townsfolk.
Stealing repeatedly from Merchant allows the player to acquire a second Main Gauche, a useful dagger for Locke. The easiest way for the player to do this is to steal from the Merchant in the side room of the Inn, then exit the Relic Shop and steal from the Green Cadet outside, switching outfits each time and allowing one to keep fighting the Merchant.