Castles in Lineage are like nothing you have seen in other games. They are walled cities with their own vendors etc. The Windawood castle has its own dungeon. Kent Castle holds sway over the town of Kent and the main city of Gludio. The orc fort gives the pledge that owns it a percentage of the slime race profits.
Castles are very faithful to historical castles both in aspect and in operation.
The Prince or Princess of a castle determines the tax on the people in the surrounding area. They can employ mercenaries and make them available to members as bodyguards. The farther away from hearth and home the more vulnerable they are which also leads to moderation of behavior towards others. If you come from a pledge that is perceived as evil you will have a harder time of it than if your pledge has an honorable reputation. Nexon USA's Shadows of Temuair is a separate game based on the same graphic engine as Dark Ages, but the gameplay of the two games are completely different.