The Keep is essentially the Courtyard of your castle. The remaining troops that are not positioned on the wall will defend it. The keep can be upgraded till level 5, and it cannot be demolished. When you first start the game, it is the only building in your castle, and when you capture an outpost, it is the only building standing. The keep controls the construction speed of the buildings in the castle. The keep also has a safe camp which stores 800 (Level 1) or 1000 (Levels 2, 3, 4, 5) of each resource which cannot be plundered by enemies when they attack. At level 1 the keep made of wood at level 2 the keep is have a blue roof and the keep changed at level 3 the keep is gray color and the roof is fully blue.