The weapon seller is a character and field map in Final Fantasy VII. He lives in a home in the Gongaga Area, east of Gongaga, which is also identified as "Weapon seller", and is visited to acquire Aeris's ultimate Limit manual, Great Gospel.
The weapon seller can only be met once the player has the Tiny Bronco. If his home is entered prior to this, it is empty and the party leaves. After getting the Tiny Bronco, the player can visit for an optional scene for "Secret Date" where the man reveals he had the Keystone but sold it to Dio. At this point, the Weapon Seller also gives information about the Temple of the Ancients and the Keystone, though he believes it only to be a legend.
The weapon seller will also trade Mythril obtained from the old man's house for items. The box on the ground floor contains a Gold Armlet, while the box on the second floor contains the manual for Great Gospel. The player can obtain either of these infinitely, but once the player has obtained both, the Old Man will no longer give the player Mythril. This way, the player can obtain 99 Great Gospel manuals. The Gold Armlet can be obtained infinitely elsewhere.