The 1980s Voltron series was based on two vaguely-related Japanese anime series (both originally produced by Toei), dubbed and strung together by American TV production and distribution company World Events. The series was not a straight dub, however, as much of the violence of the original Japanese series was removed (among other things).
The first episodes, usually the best remembered, were based on Hyakujuu ou Go Lion, and featured a team of five young pilots commanding 5 robot lions, which could be combined to form Voltron. In this era, the Voltron force was in charge of protecting the planet Arus (ruled by Princess Allura) from the evil King Zarkon, his son Lotor, and the witch Hagar, who would create huge Robeasts to terrorise the people of Arus. (This storyline is similar to those of the Toei Super Sentai shows, which formed the basis for Mighty Morphin Power Rangers.) Lion Voltron