On the menu to the right there is a link to all of our player characters.  These can be regular characters or characters that the DM plays during the game.  The character(s) that the DM plays is different than NPCs since they will have a background story and travel with the party.  

NPCs are usually shop keepers, guards, commoners, etc; all played by the DM.  Basically characters that are in the "background".  These characters don't travel with the group, but are still very important as they can be vital to a quest or part of the story.