Olivia Colasanto
Olivia Colasanto worked for her grandfather, Angelo Colasanto, who assigned her with the task of protecting his ex-lover Captain Jack Harkness after the miracle made Jack the only mortal man on Earth. Colasanto's men kidnapped Torchwood agent Gwen Cooper's family to blackmail her into surrendering Jack to their custody.
Despite travelling with two armed guards, Colasanto was over powered by Rex Matheson and Esther Drummond who had tracked the rendez-vous. She then told Jack that he would still be going with her, and informed him that she would take him to see Angelo, who was somehow still alive. (TW: Immortal Sins)
At Angelo's mansion, she explained to Jack that Angelo has monitored him for decades and kept himself artificially alive in an attempt to immortal like Jack. Olivia explained to Jack that when he was captured and had his blood drained in Little Italy in 1928, he was purchased by The Families — three influential families who sought to acquire Jack's immortality for themselves — and though Angelo did not collaborate with them, he knew that they had acquired The Blessing in 1998 and were behind the present-day phenomenon. Olivia was arrested (illegally) by the Central Intelligence Agency along with traitors within the CIA. She became a category one when corrupt CIA director Brian Friedkin let off a suicide bomb after he let down the Families. (TW: End of the Road)
