KT is an artificial person, the third created in the show, also known as Eternity Point 2 and created by Katherine and Nick in Series 2. She is Eve's adopted sister.
Series 2 Edit
KT first appeared in series 2 , episode 10. Mary told Eve and Will that she will drop the charges against Lily if they destroy KT. They destroyed a different prototype and fooled Mary. She was reprogrammed by Mary and follows her orders.
Series 3 Edit
In Series 3, KT was being controlled by Protocol Zero, but she managed to break free of it, and in the last episode of Series 3, she was against Mary and was on Eve's side. She and Eve reprogrammed the nano-virus to attack robots, because if they didn't, humans would have been wiped from the Earth. After Mary saw her late twin Helen in a simulation, she decides to take the nano-virus into her own robot body, and she gets wiped from the Earth. Eve and KT still live from that day. They decide to tell the whole world what they are, and because they do, Eve and KT go travelling. After the credits, Eve from the year 2136 returns to tell them that they need to bring the Eve from 2016 back.
Eve - Adopted Sister Edit
At first, when KT is first brought to life by Will's 'blue spark', she imprints on Eve and Will, thinking they are her 'Mummy and Daddy', since that is what Katherine programmed her to do. However, later in Series 2, Eve tells KT that she is her sister, and vows to teach her everything she knows to help her become a full artificial person.