カウンター・アームズ -終焉武装少女- is a role-playing game set in a futuristic world where weapons of land, sea, and air have been personified. As a commander, players must team up with powerful "battle maidens" known as "戦姫" to defeat the enemy force known as "機械獣" and save the world. The game features a unique idle gameplay system, allowing players to earn rewards even when they are offline. With over 100 weapon maidens to choose from, players can select their favorite weapons and challenge stronger enemies. The game also offers a comprehensive battle system where players can strategically organize their battle maidens to achieve victory. Additionally, players can enjoy various elements such as dating, increasing affection levels, and even getting married. The game boasts a star-studded voice cast, including famous voice actors such as 愛美, 伊藤彩沙, and 井上喜久子.