A Defensive Building is a structure that will defend your yard from hostile monsters, whether they are from other players or from Wild Monster Tribes . Each Defensive Building has its own characteristics. For example, the Sniper Tower is very good at damaging high health monsters from far away, while a Cannon Tower can attack many monsters at once.
Upgrading a Defensive Building will enhance its damage output, range, health, and other characteristics unique to that tower. Fortifying a Defensive Building will decrease the damage taken from enemy monsters and catapult attacks by a certain percentage. This percentage goes up the more you fortify the building. Note that not all Defensive Buildings can be upgraded or fortified.
It is important to keep in mind that as Defensive Buildings get damaged, they deal less damage to enemy monsters. At half HP, they deal 3/4 of their original damage. When almost completely destroyed, they deal 1/2 of their original damage.
Invisible to the enemy until it is too late. Triggered when a Monster steps on it, deals large damage to a small area. Place close to buildings or use walls with gaps to group attackers into a small space.
This building allows you to change out your active champ, keeping inactive ones safe on ice until you call them forth again. (Frozen champs aren't hurt even when the Champion Chamber is completely destroyed)