Emperor Palta is the primary antagonist and the ruler of the distant planet Palta, a world facing total annihilation. The core of his character and every action he takes is defined by this existential crisis, as his home planet is destined to be destroyed, leaving him and his people with only a few years to find a new world to inhabit. This impending doom serves as the driving motivation for his entire military campaign, transforming him from a simple conqueror into a desperate leader seeking the survival of his race.

As the supreme commander of the Paltan forces, Emperor Palta's primary role in the story is to orchestrate the invasion of Earth. Viewing the planet’s resources with a covetous eye, he orders his armies to prepare for conquest, selecting Earth as the Paltans' new home. To this end, he initially deploys spies to the target world, including a scientist named Dr. Polto. This action inadvertently creates his greatest obstacle. When Dr. Polto betrays the mission by falling in love with a human woman, he builds a squadron of super-powered robots to protect Earth and his half-human son, Robin. Consequently, Emperor Palta’s invasion force is continually thwarted by the very defence system his own former agent created.

While the series does not extensively detail his personal relationships, Emperor Palta’s connection to the protagonist is significant, albeit indirect. He is the master of Dr. Polto, Robin’s father, and it is his order to conquer Earth that leads to the capture of Robin’s parents and their forcible return to the planet Palta. This makes him the direct cause of Robin's orphaned upbringing and the subsequent formation of the Rainbow Sentai. His relationship with his own people is defined by his authority as their sovereign, tasked with securing their future, a duty that leads him to desperate and aggressive measures.

Throughout the narrative, Emperor Palta remains a consistent and formidable threat, though his position evolves as the story reaches its resolution. He is the leader of the alien menace that Robin and his robots battle against to defend the Earth. The story concludes with the defeat of Emperor Palta, which allows for a peaceful resolution. Following his downfall, the narrative indicates that many innocent citizens of his home planet are able to emigrate to other worlds without conflict, suggesting that his aggressive leadership was the primary obstacle to peace. Regarding his personal capabilities, Emperor Palta is depicted as the strategic mastermind and commanding officer of the invasion, but the available information on the series does not describe him possessing any individual superhuman powers or notable combat abilities beyond his authority as emperor and military leader.