NPC

An NPC or Non-Player Character is a character in the game who is not an avatar for a human being, but is coded into the game for a variety of purposes: initiating or advancing a quest, buying or selling items, offering an exchange, or simply engaging the player in a bit of amusing or informative dialog.

After the 2nd wings update, they have made Changes to the NPC's so that their names are over their heads when they are in view.

For a list of NPCs see Category:NPC.