So, in the power ranger show, Rita repulsa light's the green candle, which took away Tommy's power as green ranger. To ensure that the green power coin and green ranger powers could not be taken by Rita, it was given to Jason the red ranger. This caused problems for the rangers later on by giving up their power coins to save their parents, but Jason still had Tommy's green ranger coin so they called him back to be a temporary green ranger. How did this work? Zordon would fuse his power into the green power coin like a car battery charging up another car's battery. However, this could only be done for awhile until the green power was decimated by Lord Zedd and his monsters. Then the rangers got the thunder Zords to fight Zedd and his monsters, but they needed a sixth ranger. Thus the white ranger power coin was made and given to Tommy to replace the green rangers coin. However, in this fanfic. You aided Jason in getting the green candle from Goldar in his dark dimension. This causes the green ranger power to never be destroyed, but to fight Zedd and others like him, a seventh ranger was needed. You become the white ranger when you prove your worth by aiding Jason in saving Tommy's powers. "Centuries ago, a legendary interdimentional being known a Zordon, came to the city of Angel Grove to establish a command center for his never ending struggle against evil. With the aid of his trusted assistant, Alpha 5, the noble master sought out seven extrordinary teenagers, and gave them the power to transform into a super human fighting force. Along the way, they would need these powers to not only save Angel Grove, but the entire world. In time of great need, the young heroes could use their powers to call apon colossal assault vehicles, know as Zords. The identity of the seven remained a guarded secret. Today, that tradition continues."