Jupiter is a protagonist in SolarBalls, he is the 5th planet from the Sun, and as well as the largest planet in the whole Solar System. Jupiter is a very wise role model to the terrestrial planets. He always shares his knowledge with those who need it, such as when Earth had an idea to go to another star, he refuted the idea as they'd all freeze along the way. He also explained that he can never become a second Sun as he doesn't have the mass to become one.