A banker is an NPC that offers characters the opportunity to store items and bags. Additional bag slots can be purchased for ever-rising prices. See bank for where banks can be found and how they work.
In World of Warcraft, most cities have bankers with the title of <Banker>. When using the tracking system with the minimap they will appear with a set of sacks () at their locations.
Night elf and tauren bankers in Thunderbluff are the only ones whom have voices.
Patch changes
Patch 1.3.0 (07-Mar-2005): Certain key NPCs (such as bankers and auctioneers) in the cities and main outposts are now harder to kill. Additionally, when they die, they will respawn more quickly.