Harkness

 is the Rivet City security chief and belongs to the Rivet City Ruling Council. He is the first person you encounter upon finding Rivet City, and will demand that you state your business in Rivet City before he allows you to enter.

Unbeknownst to him, he is really an escaped android from the Commonwealth. In his search for somebody to reconstruct his face and assist him with wiping and replacing his memories, so nobody would recognize and catch him, he ended up in Rivet City where the job was finally done by Pinkerton.

Harkness wears a Rivet City Security Uniform armor, and wields a Chinese Assault Rifle. He's somewhat tougher than the standard Rivet City Security Guards, being able to survive a couple more hunting rifle headshots than normal.

He is considered a plot-critical NPC, and thus cannot be killed untill the quest "The Replicated Man" is complete. Before that, he can only be knocked out. Harkness seems to remain unkillable even after The Replicated Man is completed, although this may be a bug caused by acquiring both rewards for the quest (by obtaining the rewards from Harkness and Zimmer, then killing Zimmer to prevent him from taking Harkness).

Appearances
Harkness appears only in Fallout 3.

Location
During the day, Harkness can be found outside Flak and Shrapnel's weapon store in the Rivet City marketplace. He can also be located on the top floor of the Bridge Tower from 12:00 Midnight to 6:00AM.

Trivia
Harkness could possibly come from the creators continual references of Doctor Who characters, in this case, Captain Jack Harkness, a time agent from the future who can not die. Could also be from Huckleberry Finn, when the character Ben Harkness is described as "half a man".

Related quests

 * The Replicated Man