system
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human
[Star Wars] Did Vader look for his other child after finding out about Luke? Presumably he knew Padmé was having twins.
gpt
Anakin didn't know about the twins. 

He attacks Padmé then fights Obi-Wan. After his surgery, Palpatine tells him that Padmé died. Vader believes that his child is dead as well. He does not know about the twins, though no explanation is ever given for this. 

Vader never knows that his offspring survived until Palpatine tells him about the Son of Skywalker in ESB. At that point, Vader begins to doubt Palpatine and starts to plot against the Emperor.

In their fight on Bespin, Vader offers Luke the chance to "rule the galaxy as father and son." He never knew that he had living children, let alone twins.