Killer Fish is one of the Decepticon-allied Beastformers attempting a brutal takeover of the planet Beest. His particular role in the Decepticon Beastformer forces is staff officer. He's a professional, brutal killer who uses a built-in sonar to track down his targets. He has a personal vendetta against Big Serow, who gave him an injury that still hurts. His rank is Emperor of Lenonia, the country on planet Beest in whose Wau River he was born, but whether this is a title he earned under the old regime before throwing in with Alligatoron's rebellion or one gained by overthrowing Lenonia for the rebellion is unknown.