The Battlestar Thermopylae is a Thermopylae Class Battlestar. It was lay down as a Fenris Class Battlestar, however during construction changed was make and so it become a subclass. It also carry twelve new type of railguns with four gun turrents instead of two and those new railguns are rapid fire railgun. It also carry a two fixed forward facing railguns that fire armor piercing explosion projectile, this new type of railguns are base on the Mercury Class's main battery but are scale down and not side by side but instead are top to bottom. The Thermopylae also has a "Box" head; which was added after completed of the main hull. Some felt it was over done with guns however Admiral Arthru Wallace disagree with that view.