Voltron is a shape-changing giant mecha robot first featured in the 1980s animated television series Voltron, Defender of the Universe. There has since been a second series, made in the 1990s using CGI techniques. The 1980s Voltron series was based on two vaguely-related Japanese anime series (both originally produced by Toei Animation & Bandai, who also produced the popular Super Sentai series in Japan). The anime was dubbed and strung together by North American television 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 were based on the 1981 series Hundred Beast King FiveLion (百獣王ゴライオン - Hyakujūō Goraion), and featured a team of five young pilots commanding five 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 terrorize 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.) Despite being the first of the two robots to appear on American television, Golion's version of Voltron was regarded as Voltron III in the toyline, most likely because of its distance from Earth. (Wikipedia)