"Enemy fortress" refers to a strong and protected place controlled by adversaries or opponents. It symbolizes a place that is challenging to attack or conquer due to its defenses and the presence of opposing forces. Full definition
The fortress - building game allows users to team up with other players in real - time to attack enemy fortresses. (adweek.com)
Snake infiltrates a complex enemy fortress, faces off against an entirely new set of code - named weirdos with equally bizarre powers and saves the world by demolishing yet another Metal Gear mech. (polygon.com)