Robert Lutece and Rosalind Lutece
Robert and Rosalind Lutece, better known as the Lutece twins, are a duo of characters from the BioShock video game series. They serve as supporting characters in BioShock Infinite, where they guide the protagonist Booker DeWitt through the game's events.
The twins are revealed to be parallel universe versions of the same individual, and their role in the story is to illustrate the concept of "constants and variables." They have been praised by critics for their memorable performances and their contribution to the game's themes.