Symbol in Metropolis

Johnhan Frederson -- Lord Jehovah
Frederson lives in the highest level of the building, and also he represents the highest authority in the building. He is monitoring all the machine and labors--even they are not aware of. Meanwhile, he is also considering the fate and future of the labors. All these background setting hints that Frederson is the supreme leader, judge or Jehovah of metropolis.
In the movie, there are several scenes of Frederson overlooking the entire world in front of a window of skyscraper. The director tries to let audience understand the social ranking of Frederson in every possible way.

Freder -- Jesus
As the son of Frederson, or as the son of Jehovah, Freder is a symbol of Jesus. His relinquishing his priority and getting down to the lower class level symbolizes the fact that Jesus lives and suffers in mortal world. In the scene that a worker falls in coma and Freder takes the work and gets a worker dress reminds me of this symbol.

The Babel
Unlike the Babel in Bible, firstly, the Babel here is not build as challenging against the God. Instead, it is for communicating to the God; secondly, the failure of the Babel is due to different. Instead of by the God's interference, the Babel in metropolis is destroyed because of workers' incapability to understand the blueprint of the tower.

Scientist Rotwang -- Satan
As long as there are benevolent elements, there will be malicious elements. Deviating from stereotype, scientist here becomes a evil character. It is not difficult to imagine that all those machine is invented and designed by this guy. Indeed, those machines are the survival methods. On the other hand, machines are also the source of pain and suffering. Machines deprive the all rights and human natures from the workers.
At the end, Rotwang is kicked off the building by Frederson. In pairs, Satan is banished into hell by the God