Sergeant RL-3

 is a robotic soldier created before the Great War and a possible companion in 2277.

Background
Sergeant RL-3 has an experimental soldier personality making him "unstable," meaning that he only likes particular characters (thus the neutral karma requirement).

Effects of player actions

 * This metal patriot can be purchased from Tinker Joe outside the RobCo Facility for 1000 bottlecaps. If the player's barter skill is high enough, the player may purchase him for only 500 bottlecaps. The player character can only buy Sergeant RL-3 if their karma is neutral. Otherwise Tinker Joe will just say Sergeant RL-3 "...doesn't like the look of you." Sergeant RL-3 won't leave if the player's karma later moves away from neutral, but if separated from the player either through firing or through story events, he cannot be re-hired until karma is again neutral. In these circumstances, Sergeant RL-3 will be waiting in Canterbury Commons after a day or two, where he can be re-hired for free.
 * If Tinker Joe is dead and you did not get the robot already there is no way of getting this character.
 * RL-3 will return to Canterbury Commons if the player leaves for The Pitt, Point Lookout, or Mothership Zeta.

Stats
* Robots are considered creatures rather than NPCs and thus has an additional list of stats present for creatures.

Bugs

 * Sometimes Sergeant RL-3 will have an "exploded" view of him; all of his parts are not connected to him.
 * If in sneak mode, having the Robotics Expert perk produces the usual dialogue box with RL-3. However, selecting "Talk" does nothing.

Notable quotes

 * "You're making me angry, you won't like me when I'm angry!"
 * "Salutations, Commander! Sergeant RL-3, gutsy-class robotic soldier, reporting for duty!"
 * "Do that again and I'll put my boot so far up your ass you'll cough up boot polish!"
 * "Old war-bots never die; they just rust away."
 * "There's nothing I love more than making some other poor bastard die for his country."

Appearances
Sergeant RL-3 only appears in Fallout 3.

Behind the scenes

 * Reading the 3 as an 'E', the robot's name would be 'Sergeant R L-E' - most likely a subtle reference to actor and former Marine R. Lee Ermey, best known as Gunnery Sergeant Hartman from the movie Full Metal Jacket. R. Lee Ermey also was the voice of General Simon Barnaky in Fallout: Tactics.
 * The line, "You're making me angry, you won't like me when I'm angry!" is a reference to The Incredible Hulk, who often says this.
 * The line, "Old war-bots never die; they just rust away." is a reference to an old Army ballad line, "Old soldiers never die, they just fade away," made famous by General Douglas MacArthur's farewell speech.