The Age of Rust (also known as the Rust Age) was one of the designated periods of Cybertronian history recorded in the Covenant of Primus. It was marked by social and societal atrophy, as a demoralized Cybertron sought to recover from the failure of the Golden Age.
The Golden Age of Cybertron came to an abrupt conclusion when the colonies became infected with a Rust Plague. Possibly a deliberate attack by unknown parties, the plague was incredibly virulent and apparently incurable. Sentinel ZSee full review