I'm afraid the jury's still out on that one.
Retainers are special NPCs in Final Fantasy XIV with whom players can store their items and gil. They have a maximum storage capacity of 175 items, and can assigned to sell items in the market. Players can choose from any race/gender combination for their retainer (albeit with predefined characters for each combination), and though they have a given name they may assign a nickname to refer to them. While their appearance cannot be modified, they can wear whatever piece of equipment is on sale, as a means to advertise wares.
The player can summon their retainer with the Retainer Bell in every cities.