Surrounding a Fortress are dark gray tanks, known as Defensive Turrets. They are classified as General Enemies. They cannot move however, and will shoot at players who pass by (like a Neutral Dominator). However, they can be ANY tank Level 15 or 30, including Overseer, which will summon gray triangles to attack and chase you. Yeah, all their bullets are gray. However, a turret cannot be a Lancer upgrade tank or a Smasher, because those are purely melee tanks. It wouldn't make sense since turrets don't move. Each has half the health of an Alpha Pentagon. Created by ZathusTheMageV.
A Fortress has varying amounts of Defensive Turrets on guard (10-24), surrounding it. All must be killed before the Fortress can be entered and the boss can be fought.
Defensive Turrets can also be found in Fortress Mode, the Tower of Gladii, and many other places when listed on their pages. They are prominent in use by the Archprophet and his forces due to their simplicity.