Harkness

 is the Rivet City security chief and belongs to the Rivet City Ruling Council.

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.

He can't be killed at any point in the game.

Appearances
Harkness appears only in Fallout 3.

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.

Related quests

 * The Replicated Man