Mars is a child robot created by Dr. Yamanoue and Dr. Kawashimo on the 3rd of February, 2015. He was designed to be the most powerful fighting robot in the world. His body was made by Director Yamanoue, but his electronic brain was made by Yamanoue's rival, Dr. Kawashimo. Jetter Mars is rambunctious, strong, curious and brave.

Dr. Yamanoue is the respected and feared director of the Ministry of Science. He is very prolific, designing and creating many robots for use in battle and war. He resides on his artificial island, where most of his work is done. While Dr. Yamanoue likes to act cold and selfish, he still thinks of Mars as a son.

Miri is a robot created around a year or two before Mars by Dr. Kawashimo, making her Mars' half sister. She's kind and polite, but easy to upset.

Dr. Kawashimo is a respected developer of robotics, designing and creating many machines used for the benefit of mankind. He and Dr. Yamanoue were rivals in college, and Dr. Kawashimo was usually the one to come out on top.

Melchi is Mars' little brother, created by Dr. Yamanoue and Dr. Kawashimo. If you don't keep your eye on him, he's bound to cause mischief and chaos. If you hear the phrase "bakaruchi!" being shouted from somewhere, the best thing to do is to run away as fast as you can.