The Outposts is adding 8 Outpost meeples to Covil. These add a new strategy, allowing you to deploy your troops directly either from your Castle or from any of your Outposts. To build an outpost you need to control a territory and pay the relevant cost in Gold Coins.
Having an Outpost at the end of the game gives you extra Victory Points. Also during the “Night” phase, if there are no enemy forces in the territory of your Outpost, then that territory is considered to be controlled by you.
Important: This is an expansion, you also need the base game!