She began life in an English orphanage and was bounced between foster homes until she landed on the doorstep of Mrs. S. Despite a move to North America when she was 14, Sarah steadfastly remained the English punk, a street-smart stray with a reckless streak and a loyal heart. She's made bad choices in life, but she's always done right by her daughter, Kira. Even if that meant the pain of separation. Now, all Sarah wants is to reunite with Kira and turn over a new leaf … but her encounter with Beth changes everything.

Alison is an uptight suburban soccer mom with a strained marriage, two adopted children, and a single-minded drive to maintain the status quo. As a conservative control freak, she's the least prepared to have her self-perception turned inside out. She leans on prescription pills and conspiracy theories. But when she hits rock bottom, Alison forges herself a new path, mining the reserves of strength and bravery that seem genetically hardwired into all the Orphans.

Cosima is an eccentric, tattooed geek girl with a scientific mind verging on genius. She's completing her PhD in experimental evolutionary biology and can discuss Darwin, mono-cropping, and medical ethics in the same breath. She's dependable, driven to find answers, and, like Sarah, adaptable to extreme circumstances.

A mysterious, panicked German with health issues and a tragic end. She is the second clone Sarah encountered (Beth being the first) and it was Katja's death that got her directly involved in the conspiracy. Katja contacted Beth and told her about the existence of the clones and that their counterparts in Europe were being killed. At the time of her death, Katja was suffering from a serious respiratory illness that made her cough blood; Cosima is trying to determine if this is a genetic risk to all of the clones.

Beth is Sarah's entry point into the mystery. She is revealed backwards from the moment of her death, as Sarah takes on her identity and reconstructs her last days. By literally becoming Beth, part of Sarah's journey lies in understanding her, and she comes to deeply respect the valiant, damaged cop she so rashly switched places with.

An assassin known to have killed Katja Obinger, and probably the other deceased clones, with the exception of Beth Childs. Her last name has not been revealed. A highly disturbed religious fanatic, and Prolethean follower, she has been manipulated by Tomas to believe she is the "original" while the other clones are satanic doppelgängers, and that it is her duty to kill them all.

She was raised by the Neolutionists and works for the people who created the clones. Her birth date and nationality are unknown, although it's possible she has connections to the United Kingdom, due to her British accent. Sarah refers to her as a "Proclone."

She is presumed to be dead before the start of the series as her information is found in the briefcase Katja brought with her as proof that someone is killing them off. In "Effects of External Conditions," during the clone count, Felix says that the psycho killer clone had killed four others out of nine, presumably Katja and the three others she knew in Europe. Felix probably knew this from previous information shared by Cosima.

She is presumed to be dead before the start of the series as her information is found in the briefcase Katja brought with her as proof that someone is killing them off. In "Effects of External Conditions," during the clone count, Felix says that the psycho killer clone had killed four others out of nine, presumably Katja and the three others she knew in Europe. Felix probably knew this from previous information shared by Cosima.

She is presumed to be dead before the start of the series as her information is found in the briefcase Katja brought with her as proof that someone is killing them off. In “Effects of External Conditions,” during the clone count, Sarah’s brother Felix says that the psycho killer clone had killed four others out of nine, presumably Katja and the three others she knew in Europe. Felix probably knew this from previous information shared by Cosima.