Blue Moon is one of the five main forces of Wars World. To date it has appeared in all installments except for Advance Wars: Days of Ruin/Dark Conflict (and the Japan-exclusive Game Boy Wars titles in which it is replaced with an army known as "White Moon"). Due to the actions of Clone Andy, they are at war with Orange Star at the start of Advance Wars, though later ally with them. They are also a member of the Allied Nations.
Blue Moon's commanding officers are:
- Olaf The leader of Blue Moon, an ice cold CO. He specializes in the snow.
- Grit A very calm and collective CO. He specializes in indirect combat units.
- Colin He is an uptight CO who always tries his best to correctly carry out orders and give respect where it is due. He is also the younger brother of Sasha. He specializes in cheap units.
- Sasha She's normally ladylike, but becomes daring when she gets angry. She is also the older sister of Colin. She gets more money for her properties.
- Blue Moon is modeled after the real world nation of Russia, as well as the Soviet Union. The irony of this is that in real life the Soviet army was known as the Red Army. While in the games, the opposing team is usually colored blue.