Krycek is a
Russian-American, the son of
Cold War immigrants, who makes his first appearance in the
season two episode "
Sleepless", where as a young
FBI Special Agent, he is assigned as a temporary investigation partner to
Fox Mulder. Krycek proceeds to work with Mulder and attempts to gain his trust. It later becomes evident, however, that Krycek is actually an undercover agent working for
the Smoking Man. Krycek plays an important part in several events that are harmful to Mulder and
Dana Scully: he assists in Scully's abduction, and murders Mulder's father,
William "Bill" Mulder. Krycek also assaults
Assistant Director Walter Skinner and acquires a secret tape from him which reveals a
US government coverup regarding alien visits to
Earth. After a botched attempt on Scully results in the death of her sister, the Cigarette Smoking Man attempts to kill Krycek with a car bomb, but Krycek escapes. Krycek is later found in Hong Kong, where Mulder discovers that he has been selling information from the digital tape containing the MJ documents. Under the influence of the
black oil, Krycek returns the tape to the Smoking Man, in return for knowledge of the location of an alien ship. The black oil-controlled Krycek goes to the ship, which has been moved to an abandoned missile silo in North Dakota. The black oil extracts itself from Krycek, leaving him locked indefinitely in the silo with the ship. Krycek is next found during an FBI raid, and taken into custody by Mulder and Scully. They learn that Krycek was recruited by an extremist militia group on a salvage hunt from the silo in North Dakota, and he informs the agents they must track the source of an extraterrestrial rock, brought to America by a foreign diplomat, to a
gulag in
Russia. The hunt leads Krycek and Mulder to
Tunguska, where they are held captive until Krycek maneuvers his own release. Mulder attempts his own escape, taking an unconscious Krycek with him. When he awakes, Krycek separates into the woods only to encounter a strange group of Russians, all of whom have missing left arms. The men amputate Krycek's arm as well, to keep him from being used in black oil
experiments. Eventually, Krycek graduates into a more powerful role within this group. He uses any knowledge he has to gain leverage with the syndicate. He even has had romantic ties to their secretary,
Marita Covarrubias (who apparently was using Krycek for her own means in assisting Mulder). Due to this double-crossing, Krycek is temporarily held captive by the
Well Manicured Man. Krycek later appears to Mulder as a friendly messenger to tell him that a war has begun, and that Mulder must "resist or serve". Later in the series, Krycek can be seen switching sides as it suits him, occasionally helping Mulder, the Cigarette Smoking Man and other people. He attempted to blackmail Skinner with infectious
nanotechnology, but ended up being thrown into a Tunisian prison by the Cigarette Smoking Man. Later, when Mulder was abducted by aliens and returned in a deathlike state, Krycek attempts to again blackmail Skinner, offering the means to save Mulder's life in exchange for Scully's baby. Skinner refuses, and Krycek has a violent confrontation with
John Doggett before escaping. In the
season eight finale, "
Existence", Krycek is shot dead by Skinner, during an unsuccessful attempt to kill Mulder. Krycek's ghost briefly showed up to help Mulder escape a military base in the series finale. == Conceptual history ==