The Rise of the Rebellion is an event that happens prior to the First Mission and the First Modern War. Starting in 2026, the Rebellion Army launches an assault that pushes the Regular Army forces into the brink of destruction. No one expected this except for the Rebels who came up with these plans. The fault was mostly in the hands of the Regular Army commanding officers, who failed to realize the value of information that the Regular Army intelligence division had provided. With superior numbers of troops and weapons, the rebels overwhelmed the Regular Army in all aspects. Seeing their disadvantage to carry out direct attacks against the Rebellion, the Regular Army then decided to carry out numerous special operations and create certain vehicles to accompany their commandos. Not long after, a newly designed tank, code named "Metal Slug", was forced into production. The stockpiling of Metal Slugs continued for two years in preparation for a massive assault against the Rebellion.