The five Advance Wars countries are all unique in their own ways, and are probably based on real world nations from World War II. Here is information about all five powers.
Orange Star
Color: Red
Training Missions: Controlled
Campaign Mode: Controlled
War Room Mode: Controlled (Enemy if player controls a Blue Moon CO)
Versus Mode: 1st Army
Resemblance To: United States of America
Headquarters: American Skyscraper
Orange Star CO Leader: Nell
Available Commanding Officers: Andy, Hachi, Max, Nell, Sami
Brief Bio: Early in history, the Orange Star forces clashed with Blue Moon rebel forces that seized the eastern end of Orange Star. Eventually, Olaf's forces entered Orange Star, but Nell drove them out. Weeks later, Olaf invaded again with a full force. In Advance Wars 1, Andy and the player advisor forced Olaf and Grit back into Blue Moon. Orange Star then swept through Yellow Comet and Green Earth before discovering that Black Hole was the true enemy. After Sturm was defeated in Cosmo Land, peace returned briefly. In Advance Wars 2, Sturm returns, and Orange Star must repel Flak and support its allies against Black Hole once more.
Orange Star was originally called Red Star in the Japanese version, but was renamed for the international release to avoid political associations.
Blue Moon
Color: Blue
Training Missions: Nonexistent
Campaign Mode: Controlled
War Room: Main Enemy (Controlled if player controls a Blue Moon CO)
Versus Mode: 2nd Army
Resemblance: Russia
Headquarters: Russian Palace
Blue Moon CO Leader: Olaf
Available Commanding Officers: Colin, Grit, Olaf
Brief Bio: Blue Moon separatist forces achieved early victories after Olaf and Grit joined them. Olaf twice invaded Orange Star but failed both times. After Sturm betrayed Blue Moon, Olaf joined the Allied invasion of Black Hole and helped defeat Sturm in Cosmo Land. In Advance Wars 2, Lash invades Blue Moon, and Olaf must reclaim his homeland before striking Black Hole directly.
Green Earth
Color: Green
Training Missions: Nonexistent
Campaign Mode: Controlled
War Room: 2nd Enemy (Controlled if player controls a Green Earth CO)
Versus Mode: 3rd Army
Resemblance: Germany
Headquarters: German Castle
Green Earth CO Leader: Eagle
Available Commanding Officers: Drake, Eagle, Jess
Brief Bio: Green Earth was drawn into war after Clone Andy attacked its territory. Mistaking the real Andy for the culprit, Eagle launched failed invasions into Orange Star and Blue Moon. Once Sonja uncovered Sturm’s deception, Green Earth joined the Allied forces and defeated Sturm. In Advance Wars 2, Hawke leads the Black Hole invasion of Green Earth, forcing Eagle, Drake, and Jess into a desperate defense.
Yellow Comet
Color: Gold
Training Missions: Nonexistent
Campaign Mode: Controlled
War Room Mode: 3rd Enemy (Controlled if player controls a Yellow Comet CO)
Versus Mode: 4th Army
Resemblance: Japan
Headquarters: Japanese Palace
Yellow Comet CO Leader: Kanbei
Available Commanding Officers: Kanbei, Sensei, Sonja
Brief Bio: Yellow Comet remained largely inactive until the wider Black Hole war spread into its territory. Orange Star’s pursuit of Olaf left Yellow Comet devastated, but Sonja eventually uncovered Sturm’s true role in the conflict. In Advance Wars 2, Adder invades Yellow Comet, and Kanbei’s forces must repel him before joining the larger assault on Black Hole.
Black Hole
Color: Black
Training Missions: Main Enemy
Campaign Mode: Main Enemy
War Room Mode: Controlled if player controls a Black Hole CO
Versus Mode: Nonexistent
Resemblance: Alien Country
Headquarters: Something that shoots up to the heavens
Black Hole CO Leader: Sturm
Available Commanding Officers: Adder, Flak, Lash, Hawke, Sturm
Brief Bio: Black Hole is the most technologically advanced and dangerous army in the series. Sturm manipulated Blue Moon into attacking Orange Star while he struck Green Earth directly. Though defeated in Cosmo Land, he returned in Advance Wars 2 with four subordinate commanders. Black Hole again launched invasions across all four nations until Hawke eventually betrayed Sturm, leaving the remnants of Black Hole weakened but still threatening.