The Invasion of Io was a major battle of the Combine-Aurelian War, a conflict between the inhabitants of the Aurelian Sector and the Empire of the Combine Race. On January 13th, 2054 (1621 N.E), Combine forces had raided Tiphon City, the planetary capital, where about 400 civilians and 50 soldiers were killed. This forced President Benedict Cleverland into ordering into sending in reinforcements to take on the small invasion force. A day later, as Rebel forces collide with Combine forces, Nero and all what remains of the Germanican Empire soon joined the fight in order to defeat the foe they shared with their former Terran rivals. Marauder-class Frigates were soon deployed to save the majority of the Terran civilians while the rest were conscripted to aid their comrades. Soon, Tiphon City was reclaimed, along with Io's moon, which was used as a base of operations for the enemy. By January 15th, the Combine were driven out and the GRA and the Germanicans have won the battle. This led into an unlimited amount of supplies Rebel forces who fought in the second invasion of Vadder.