This dangerously ruthless man remains an absolute enigma since we first saw him. He has alternately warned, helped and hindered Mulder and Scully in their quest for the truth. He has stated clearly that he has no intention of following the way of his predecessor and will not risk his neck for them. From his no-nonsense style and his use of deadly force, it is possible that X is somebody high up in the CIA or possibly the NSA. When Mulder and Scully investigate a scientist whose shadow has come a terrible weapon, X takes a key witness away from them. Mulder tells him that they will not have anything to do with him, X simply tells him that "it is a dangerous time to go it alone". We learn that he was once like Mulder but now he plays the "game" and this game is a deadly one. When Mulder chases a unknown individual who has stolen Scully's blood sample, it is Mr. X that cool bloodedly executes the man showing Mulder that this may be the only way to find out the truth. Later, he arranges for Mulder to do the same to the Smoking Man's henchmen when they come to search his apartment. Mulder fails to do this, prefering to be at Scully's bedside. Mulder realises that X was leading him down a path of darkness, which begs the question which side is Mr. X on?