Everyone Knows This is a Problem
If everyone knows something, there’s no need to explain it. Everyone knows who Zrrt the Legless Conqueror is. Everyone, of course, except an audience. This causes a problem when presenting worlds where something critical is just commonplace knowledge. People of fictional worlds explain Zrrt as often as we explain doors. They’re just there. Worldbuilders, especially those working in narratives or with an audience, must communicate critical information about a world that would not naturally be a topic of conversation.
This problem becomes even more of an issue in game worlds where players take on the role of a person from that world. Things like the recent history of a world, important factions, and the location of nearby towns and cities should be known by anyone that lives in this world. However, the audience, or the players, do not live here and do not know this information.
This problem is solved in a number of ways. Simply explaining this information is the most straightforward, although it comes at the risk of lore dumping. It can also be solved by using an audience surrogate, using contextual clues, or simply by having characters be from out of town and unfamiliar with the region (a type of audience surrogate).
Solutions:

