"Zombie Army" is a series of cooperative third-person shooter video games developed by Rebellion Developments. Set in an alternate history during World War II, players fight against hordes of undead soldiers and supernatural creatures. The games combine elements of horror and action, featuring a variety of weapons and tactics to defeat enemies. The series includes titles like Zombie Army Trilogy and Zombie Army 4: Dead War. Players can team up with friends or AI companions to complete missions, solve puzzles, and uncover the story behind the zombie outbreak. The games are known for their intense gameplay and engaging multiplayer experience.