Alice Carter
She has a connection to something mysterious from Jack’s past, his daughter and lives in Cardiff with her son and Jack's grandson, Steven – who, like every child in the world, is briefly taken over by the 456. She appears in part one when Jack visits her and wants to do some tests on Steven. Then, Alice tells her father to leave, and he does to visit Dr Rupesh. Alice's son, Steven, thinks Jack is his uncle.
It is unknown but not entirely impossible that she have inherited some of her father's regenerative abilities although no evince has been shown yet.
Candidates for mother
While it is possible that Alice's mother has not been met, candidates include Jack's unnamed wife (TW: Something Borrowed).