Sarah Duffy

Sarah Duffy varies as a side character and a main character depending on the story she's set in.

A Cold Love Story
Sarah in "A Cold Love Story" is actually the antagonist of the story. She had an abusive childhood and one day her parents ran over a child, and it being blamed on her, she has to hide the body.

C-6
Sarah's past has been, so far, vague. She's stated that even though she wants to kill Ponder, she wants PuppetGAME to continue.

C-ACLS
This Sarah is nicknamed Cold and is from a version of A Cold Love Story where she kills John.

Trivia

 * C-ACLS is an acronym for "A Cold Love Story".