Carl A. Rotwang was a German scientist and inventor, who lived in the Berlin Metropolis and created a humanoid robot named Maria. He, along with Maria, were members of the German version of the League, Die Zwielichthelden. Rotwang sometime passed away prior to 1941.
Rotwang appears as the main antagonist in Fritz Lang's 1927 film Metropolis. In the movie, the love of Rotwang's life was a beautiful woman named Hel, who rejected him and chose his rival Joh Frederson, the master of Metropolis. She died giving birth to his son Freder.
Rotwang built his robot in an attempt to recreate Hel, and lost his arm in the process. He wore a functional metal prosthetic hand in its place. However instead of finishing his robot in Hel's image, he was ordered by Frederson to create an immoral copy of Maria (a worker girl who was admired as a sort of prophet figure by the poor inhabitants of the underground Workers' City) - in order to disrupt the real Maria's influence over the workers.
The robot Maria then stirred the workers into rioting and causing murderous chaos throught Metropolis.
Later, Rotwang became delusional and believed Maria to be his lost love Hel. Eventually he fought Freder on the roof of Metropolis' cathedral, and ended up falling to his death.