Towers are defensive buildings placed at intervals along your castle wall. When the player first downloads the game, they will automatically have four empty tower spots. As you progress in the game, you can unlock higher and higher level towers. The number and level of towers you have affects the amount of troops you can have stationed along your castle wall. The more troops you can have along your castle wall, the less likely it is that an attacker will make it past all three of your flanks and get a courtyard bonus.
Towers have five levels, each progressing in the amount of troops you can station.
To have a certain level tower, you must have the corresponding level castle wall. For example, if you have unlocked level three towers, but you haven't upgraded your wall yet, you won't be able to build the level three towers. This is a trait towers share with castle gates.
The color and general style of each level of tower progresses in the same way as your castle keep.