This page reads more like a plot summary than a character page.
In 2007, the man was chased across a rooftop by Jack Harkness and Gwen Cooper of Torchwood Three. Using retcon gas, Jack's kidnapper rendered Jack unconscious and took him aboard a plane to Chernobyl. When Jack awoke on the plane, his kidnapper was not threatened by him and drew a gun, telling Jack that it was loaded with practice range rounds, meaning that the bullets would enter Jack and not exit. Not answering Jack's questions, his kidnapper shot Jack dead. After Jack resurrected, his kidnapper commented on how fascinating it was that Jack came back to life every time. Despite Jack's protestations, the man pushed Jack out of the plane at 30,000 feet over Chernobyl, killing him once again.
After Jack's fall, his kidnapper gathered all of the pieces of Jack he found and brought them into the local hospital where Jack reconstructed himself and was resurrected once again. The man was fascinated by the fact that despite the fact that they couldn't even find all the pieces of Jack, he returned to life again. Jack's kidnapper ignored Jack's attempts to get answers and promised that he would reveal the purpose of Jack's kidnapping soon enough. The kidnapper performed an x-ray which revealed that all of the shrapnel and bullets Jack had been killed with over the years were still within him, just healed around. The kidnapper moved onto to draining Jack's blood and continued to ignore Jack's attempts to get answers.
As the kidnapper drained another bag of blood, he was confronted by Gwen who had been able to track Jack to Chernobyl. The man activated the MRI, which pulled Gwen's gun from her hand. The two briefly struggled, but Gwen managed to shove him against the MRI machine. The man taunted that they had been "doing this since '28" and it was a little late to try and stop them. The kidnapper broke free, captured Gwen and threw her into the back of the truck he had been filling with packets of Jack's blood. When the man returned, he found Jack apparently reaching for a dropped scalpel and taunted him. However, Jack had actually been reaching for the controls to the MRI machine. When Jack activated it, all the bullets and shrapnel inside his body were pulled to the MRI machine with the kidnapper right between Jack and the machine. All of the bullets and shrapnel passed through the kidnapper, ending with one of the bullets going through the man's head, killing him.
In the aftermath, the Three Families dosed Jack and Gwen with retcon gas so that they forgot the events of the day. Jack and Gwen were left on the rooftop they'd originally chased the kidnapper on with the impression that they'd forgotten something important, but no idea what.
In 2011, while searching her brother's computer, Holly Mokri found the flight plan for the kidnapper's flight to Kiev with Jack. The man was also listed as Z on Miles' collage of pictures of people related to Miracle Day in his notes. (WC: Web of Lies)