Scavenged from parts by a wandering trader named Tinker Joe, Sergeant RL-3 is a General Atomics Mister Gutsy model, created for mobile attacks prior to the Great War. Utilizing both plasma and flame as its main weapons system, "Sarge" is always ready with a quip ("Pain is just weakness leaving the body! Hooah!"), but has an experimental "personality," making it difficult for Tinker Joe to offload him.
He always refers to the Lone Wanderer as "Sir," regardless of their gender.
RL-3's plasma rifle is incredibly inaccurate, usually missing a stationary super mutant. Oddly, he is much more accurate when attacking the Lone Wanderer (if turned hostile), and will hit even over a long range.
RL-3 can be asked to activate the purifier during the quest Take it Back!. If one does not have Broken Steel installed, he will refuse, and exhort the Lone Wanderer to finish the work their father started.
If one does have Broken Steel installed, RL-3 will willingly start the purifier, aware that the radiation in the control chamber poses no threat to him, and he will be referred to as a hero in the epilogue. When the game resumes after the epilogue, RL-3 will be waiting in the infirmary at the Citadel.
If one boards Mothership Zeta, RL-3 will wait next to where the player character is abducted from.
When in incredibly dark areas (e.g. Vault 87) RL-3's eyes will glow.
The line, "You're making me angry, you won't like me when I'm angry!" is a line from the 1970s TV show The Incredible Hulk.
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.
The line, "There's nothing I like better than making some other poor bastard die for his country," is based on the quote from American General Patton, "The object of war is not to die for your country but to make the other bastard die for his."
The line "Kill them all, let God sort them out!" is based on a Latin quote (Caedite eos, novit enim Dominus qui sunt eius) from Cistercian church leader Arnaud Amalric, during the Albigensian Crusade.
RL-3's designation closely resembles the initials of actor and former Marine drill instructor R. Lee Ermey (RL-E).
Xbox 360 One may not be able to talk to RL-3 when trying to rehire him at Canterbury Commons. If this happens simply reload the most recent save and go back. He should now talk to the player character, allowing one to rehire him as normal. [verified]
PCPlaystation 3Xbox 360 With Broken Steel installed, RL-3 possesses a staggering amount of health at higher levels. At level 20 he has fully several thousand HP, more so than even a super mutant behemoth. This is due to a badly adjusted setting concerning RL-3's leveling, which grants him 350 HP per level gained. Dogmeat and Fawkes are similarly affected. This only occurs if Broken Steel is installed prior to meeting RL-3, otherwise RL-3's level does not scale and his health is fixed at 350. [verified]
PCPlaystation 3Xbox 360 If in sneak mode, having the Robotics Expert perk produces the usual dialogue box with RL-3. However, selecting "Talk" does nothing. [verified]
PCPlaystation 3Xbox 360 RL-3's plasma projector uses the laser rifle's firing sound, not the usual Mister Gutsy sound effect. [verified]
Playstation 3Xbox 360 When traversing over mountains, RL-3 may get stuck on, or in, a rock. [verified]
PCPlaystation 3Xbox 360 Some events cause RL-3 to become hostile towards everyone (including the player character) indefinitely after ever being dismissed from the party. These include destruction of the combat inhibitor, him witnessing Tinker Joe die, Crow's death in general (because RL-3 has some sort of scripted-in co-affiliation to Crow like he has with Tinker Joe) and investing any money in Crow's business during the Merchant Empire quest (because the game treats merchants one has invested in like they were dead in some regards). [verified]
PC RL-3 may remain frenzied even if his combat inhibitor appears repaired. To check, open the console, click on RL-3 (or enter prid 94285), and issue the getav aggression command. If it returns 3.00, RL-3 is frenzied, which can be repaired with setav aggression 1.
Playstation 3 RL-3 can be waiting in the Commons even if one did not purchase him and he can be hired for free. [verified]
Xbox 360 RL-3 will sometimes attack friendly or neutral non-player characters. He has a knack for attacking everyone inside of the Republic of Dave capitol building, and Scribe Yearling and the Brotherhood of Steel knights inside of the Arlington Library. What is odd is that one must walk to a certain spot in these areas before he will turn hostile towards them. To fix this, simply have RL-3 wait in an area away from these spots, but don't dismiss him. Conduct one's business and when it is concluded, reacquire him. (If one wants RL-3 in the Arlington Library to help them out with the raiders further in, just go another way that won't trigger this bug.)[verified]
PCXbox 360 It is possible to recruit Sergeant RL-3 at the same time as another companion by dismissing your current companion, then speaking to Tinker Joe and purchasing RL-3, followed by quickly re-hiring your old companion before RL-3 speaks to you. This glitch works with Butch, Charon and Dogmeat. Leaving the Capital Wasteland to Point Lookout or the Pitt will need one to fire all companions. This glitch cannot be repeated. [verified]