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Movies like Transformers: Five Faces of Darkness (1986)

Following the events in Transformers: The Movie, the Decepticons have fled and the Autobots are victorious under the command of a new leader, Rodimus Prime. In the midst of the celebrations, the Autobots are attacked, leaving the Decepticons the obvious suspects. Meanwhile, the mysterious Quintessons attempt to conceal a dark secret as old as Cybertron itself.