The Thirteenth Legion (also known as the Lost Legion) was an ancient group of Autobots that abandoned Cybertron after the wars that consumed the planet. They settled on the planet Antilla where they formed a thriving community with advanced technology. The colony continued peacefully for some time until an asteroid shower impacted the planet and infected the Autobot colonists with Cosmic Rust. Unable to discover a cure despite their advanced technology, the colonists all died. Cosmic Rust