Fallout Wiki
Fallout Wiki


Rex is a permanent companion that can gain a benefit after completing his quest from The King "Aint Nothin But A Hound Dog" you do not need to kill The King in order to recruit Rex. He is also a part of the Achievements "The Whole Gang's Here" and "Ol' Buddy Ol' Pal"


Where is it said that he doesn't like hats? --Kris User Hola.jpg 13:29, September 15, 2010 (UTC)

On his card. Tezzla CannonUser Tezzla Dog.jpg 13:34, September 15, 2010 (UTC)
His card? what? where?
--Kris User Hola.jpg 23:26, September 17, 2010 (UTC)
OOOOOOh ok! I've been trying to figure out why people were saying that for a while.
The King mentions 'in game' that Rex dislikes Rats and Hats, and people wearing Hats. That is the best reason people are mentioning this.
He really does hate hats, I've had him tagging along for a bit now and he looks like he's about to jump any npc with a hat on after growling and barking at them. I keep waiting for him to actually maul someone, hasn't yet sadly -.- Since there's no cats to be found in the Mojave, its probably a safe assumption that he'd go after them as well if he could find ant...Cat, rat...hat...they all rhyme and that seems to be most of the basis for his dislike.

I had problems with Rex attacking the Legion commander in Cottonwood. Some dialogue with him mentioned the courier inquiring how to get his hat, so I assume that's why Rex attacked.

I have noticed that when I tell him to wait as I decorate my Wolfhorn Ranch house and he growls at me because I wear a bandana!! GamerAddict7796 09:08, May 2, 2011 (UTC)

In addition I returned to Rex after dismissing him to the Kings after a while wearing the Boone's reward 1st recon hat and he growled at me and the first conversation option was about how he does not like people wearing hats. 02:45, August 30, 2020 (UTC)

Article name

I changed the article name to what it says his full name is here: [1] I was thinking simply along the lines of article names being full names of everything with a name, but if someone thinks it should just be "Rex", feel free to change it back. (I know I don't have to give permission, but I also know not everyone will like how the name is right now) -- Juicestain09 19:52, September 15, 2010 (UTC)

Short name seems much better and practical. It's just not good to even write the serial number into it. If at all, "Cyber-Hound Mk. III" would be correct. Still, "Rex" is much more fitting. --Mr.Lexx(talk) 19:54, September 15, 2010 (UTC)
I have no objection to it, personally. I've already adjusted the Rex page to link here, and Rex (Fallout: New Vegas) redirects here. --Kris User Hola.jpg 19:55, September 15, 2010 (UTC)
My opinion is we have the name as his full name, but we could make some redirects with parts of the name to make is easier to find him, no? --Juicestain09 20:05, September 15, 2010 (UTC)

I'm changing it back because the full name can always go in his info box. Shadowrunner56 20:07, September 15, 2010 (UTC)

How does everyone like the first paragraph and the infobox title? --Juicestain09 20:14, September 15, 2010 (UTC)

Is everyone happy with Rex (Fallout: New Vegas) as the title? JASPER//"Do you like hurting other people?"UserRichard.png 20:09, September 16, 2010 (UTC)

Lupa's Brain Bug?

(Hardcore mode/360) After replacing Rex's brain I noticed that his health started displaying as 100/0, and he ended up dying frequently. I was stubborn and kept reloading until he died fighting a single spore plant at level 20. Anyone else experience this bug?

I am currently also experiencing this bug. Pretty much everything I fight 1 or 2 shots him. I have no idea how to fix this.
Same here. Also, whenever he gets hit, it's (HP)/0. you can't heal him this way

Where does Rex respawn?

Went into the Strip and lost both Rex and Boone. Does anyone know where Rex reappears if lost? When I try to get another follower, it still tells me I have too many. Help!

I believe he re-spawns at The King's. He should be in the lobby. I found him there.

I told Rex to go to lucky 38 to get ED-I than I told ED-I to go there than I go there to get Rex and he's not there, where did he go.

Give it some time, and a message will eventually pop up saying he's gone back to Freeside (after being in "phantom" companion mode keeping you from recruiting others and causing the dialogue regarding him still being with you when he's not). Unfortunately, I've checked King's several times, and Rex hasn't shown up yet, even after sleeping in and outside the area. Same thing happened to Arcade Gannon.
Can't find Rex either. One moment he was behind me in Gomorrah, when I turned back, he was no longer there and I couldn't find him. Is there any official walktrough or hints or something from Betashade? EDIT: So, I'm roaming the vault 34 and out of nowhere, Rex appears. Almost shot him.
Something similar happened to me i told him stay at Lucky 38 next time i came to check on him he was gone.Lost both him and Lily this way... and a bunch of good equipment

I told ED-E to go home and went to get Rex at Lucky 38 where I saw him last, but when I get there the only person that's there is Veronica. Rex appears to be completely gone.

Lost Rex, looked at King's and Lucky with no luck' I've also tried the Vault (22?) elevator trick but to no success. The I suppose "minor/lesser" companion slot is open (I can get ED-E to tag along at any time) so it's not like he's waiting somewhere. Some more insight would be nice.

After dismissing Boone (so that he wouldn't annihilate the Legionaries), I fought Lupa at the Fort while Rex was with me, and after I defeated her, he was gone from the camp. NPCs still comment about him all the time. I waited a few days, nothing. Went back to Freeside and searched up and down, no dice. So now I can't recruit any other non-human companions, and I can't heal him. Any special tricks to get him back?

I asked rex to wait for me inside Lucky 38. He was there at first.. but after awhile he disapperd. This most be a bug! :(

To anyone and everyone experiencing this problem: I would suggest using the Companion Dismissal Terminal at the Gun Runners station (oustide Freeside) to force-reset the companion back to their original location. It's worked for me for other companions.
Ok this may help you out trying to find REX check your world map and there is a arrow with REX at the Bottom of the arrow just find that and you will find REX in no time ^_^.

Some people don't get the triangle with the NPC's name. Me for example which is why I'm here. Just gonna try a placeatme and see what happens. Also remember to sign your posts please. -Setari (talk) 23:54, June 13, 2013 (UTC)


it might be worth it to make a note somewhere in the article that Rex means king in latin and that it is The King that owns Rex. i put that in a triva section but someone quickly removed it (should i have not added it?)--Ohno21212 15:08, October 30, 2010 (UTC)

Rex does mean king, but it is also the stereotypical dog name in various media, so I don't think a note on the latin origin is especially noteworthy. I removed the trivia for two reasons: we don't have a trivia section - it's either behind the scenes or it's a note - and the comment about the fittingness of the name is a subjective judgement, so not relevant to the article. No big deal to me, though, if the latin meaning is noted without commentary.--Gothemasticator 15:22, October 30, 2010 (UTC)
Here's a theory. Perhaps the "King in Latin" thing was Ceasar's idea. There's a good 150 year gap (when did he come from Denver to Nevada? When did Caesar become his sidekick?) in Rex's timeline as it is, and Caesar might've coined his 'new', Latin name upon discovering Rex. The way I see it, Rex's name is a double wammy of multiple meanings. -- 07:05, November 29, 2010 (UTC)
Ah ok that makes sense --Ohno21212 15:33, October 30, 2010 (UTC)

Just dont forget Rex has a painting of a bull on him and Caesar's Legion's logo is a bull TheVaultDweller112

Rey=King Rey, the possible brain-donor, bears the 'King' name as well (in Spanish.) Compatible donor, indeed! -Anon.

Bug That elusive Rex

Finished his quest (got that Fiend's dog's brain), took him around for a quest or two after a while, left him in Lucky 38. Tried to talk to him again after a few quests (or maybe more than a few), he's just lying there and my only option is to pickpocket him. Fast forward a couple of dozen of hours: I did 3 of the endings (up to now), in all of them Rex succumbs to the horrors of the desert. Went to get him this time to see if playing with him a bit more would help, no Rex anywhere (King's place included). Almost forgot: PS3 (all this bar his quest after the update)

Edit: Just talked to the King for the King's Gambit quest. He asks where Rex is and apparently (by my possible answers) Rex is dead. Problem is I'm NOT playing Hardcore and Rex was left in my room in 38. Renio 10:52, November 9, 2010 (UTC)
If you get a brain from that old lady the king or somebody tells you about he wont die. And you dont have to pay her seven hundred caps just kill a dog and take brain(I recomend ray)
He stated he put the Fiend's dog's brain in, which is one of the 3 you were told about, Violette (sp?).

Special Attack?

Rex seems to be able to knock down enemies much of the time, very useful, but I see no mention of it in the article. The first thing I did after acquiring him was to grab a brain from Gibson scrap yard, which made him more vicious, so I'm not sure if it is related to that brain in particular. Can't say I've noticed many other enemies being knocked down by companions, (had 3 others so far). Is it just some random thing or have others noticed the same?

I've seen Rex knock down enemies too. This was with his default brain. -- 00:38, December 6, 2010 (UTC)

Rex dead

You guys know of any way to resurrect rex without his body? he died and i didn't even noticed!!!!

prid and his ref code should bring his name up in consul then use moveto player. That should move his entire body to you might want to noclip in the air a bit so it doesn't get stuck in the ground or fall though it. 08:39, December 18, 2010 (UTC)
wtf is a prid?

Lose Rex permanently after completing Dead Money?

Under bugs, the page mentions "(xbox) When you are knocked out in Dead Money when you escape, you will be unable to find Rex again." Is this true? Is this permanent? Or does Rex show up again in Freeside after a few days of returning from the Sierra Madre (i.e., after completing Dead Money)? Crap, if you lose Rex permanently just for playing the DLC Dead Money, that is a most unfortunate bug! (In other words it is a P.O.S.) Is there any way around this on the xbox -- like dismissing him before starting Dead Money? --Sp3lly 18:17, February 8, 2011 (UTC)

Edit: "I've tried makeing him wait at the Lucky 38 before starting Dead Money, so if your thinking about trying that, don't even bother cause that doesn't even work. But one thing I didn't know is that you can get Rex back after dismissing him(In regular game)? Cause I tested that on Lily and no text option showed up to where I can get her again." -Scribbles.
Edit: "It's me again and no you don't lose him you can find him at the Kings place in Freeside, after beating the DLC." -Scribbles.

No, you can't. I JUST completed the DLC and Rex is nowhere to be found in the Kings' place. -Setari (talk) 23:58, June 13, 2013 (UTC)

Rex Endings

Does anyone know what ending you get when you place one of the ncr guard dogs their brains into him? Since it doesn't give any bonus i haven't tried it out myself but i'd really like to know. =) -- (BlitzKrieg-BoB 20:38, February 15, 2011 (UTC))

Edit: I tried getting this NCR Guard Dog Brain or whatever it is called and after killing about 20 NCR Dogs, still no brain drop. I tried looking for it's ID but couldn't even find it on the new vegas misc item list. Does this brain even excist? -- (BlitzKrieg-BoB 20:38, February 15, 2011 (UTC))
I don't think there is an NCR guard dog brain. 101Phase
It is said that there is, I assume it's the same ending he'd get if he died.

Rex Attacking Companions and NPCs

Not sure if anyone else has had this problem on the 360, but sometimes when I returned to the Lucky 38, Rex would growl and start fighting Boone, Cass, or Arcade to the death (mostly Boone). Despite being in casual mode, Rex would die (without the announcement box appearing), sometimes gruesomely, and I could loot his corpse as normal. This has happened when he was left at the 38, not as a current follower. However, as a current follower at Hoover Dam, sometimes he'd randomly attack a couple of (non-hostile) NCR soldiers when I was looking for Col. Moore. Just putting it here, since I don't know if it's just a one-time bug or something that can be confirmed by others for inclusion in the Bugs section. I don't know of a fix other than to reload and quickly rehire Rex when he starts growling in the 38, or make him wait away from those particular soldiers in Hoover Dam. 04:59, February 21, 2011 (UTC) Kaz

Confirmed on PC. just happened to me. About 3/4 into game from what I can tell (1st run), roughly.. most non-main quests completed, but Im playing slow the main one. Nothing I can think of out of the ordinary. Rex previously dismissed -within- the L38 suite itself, as I was swapping for EDE; after a few game hours, came back and Rex is attacking.. mainly Cass (seemingly just because she appears to be the closest at the time I'm entering the room); also, was not able to have Rex 'heel': i.e, he was not responding as a companion at all. Playing a 'neutral/goodish' char, kinda going for independent New Vegas/lined up with NCR; Cass wearing non-faction power armor. Will update if I learn more how/why. Only thing I can come up atm is that Rex is somehow reverting back to his hatred for hats? (Since all companions have some sort of hat/helmet..)
Update: after a few save/reloads I think this bug affects the non-human companion instead. A couple of unsuccessful tries, but I managed to 'talk' to Rex just as I entered the room, after having dismissed EDE on the street.. Immediately, EDE started shooting Cass/Boone.. don't know how far back I'm gonna have to go on this one- agh!!
Update2: After trying unsuccessfully a couple different things, I am now convinced this is an instance of [bugs (Patch]; Even though my version is; I normally don't leave stuff on companions other than weapons and ammo, but, following the idea from that note, I realized i had left a few purified waters -both- on EDE and Rex, which I hadn't done before (one or the other, but I don't think i had left them both.. I tend to use Rex or EDE as 1st option pack mules since they don't carry the additional weapons/armor/ammo that human companions do, but I usually remove all their stuff as I go by homes) .. so anyway, going back a couple saves, removing the P/waters from Rex and dismissing him.. no trouble so far, about 30 mins realtime (6 hs or so game time?) in new save so far, 2 times back to '38, no problems.

a problem that i had (i might be patched now) i went to north vegas square and rex would attack jules and turn north vegas hostile i fixed it by loading a previous save{{Infobox.-- 14:05, January 27, 2013 (UTC)}}

Rex in Fallout 3?

I was playing Fallout 3 one day, and when I was in Little Lamplight, I found a dog named Rex. Since FNV took place WAAAAY after Fallout 3, could this be a Rex before he was a cyber dog?

--WisestWiseGuy101 00:11, March 8, 2011 (UTC)WisestWiseGuy101

Not a chance. Rex (Lamplight Caverns) is a normal dog, so he should live the 15-20 years dog normally do (barring any mutations, of course). Rex (cyberdog) was born five years before the Great War. Without technology, Rex (cyberdog) would have died a) during the bombing or b) around 2092 (20 years after his birth). So that means if Rex (cyberdog) and Rex (Lamplight Caverns) were the same dog, if would mean Fallout 3 would have to take place sometime between rgiht after the bombs fell and 20 years after the bombs fell, as to make sure that Rex (cyberdog) stayed alive. But since Fallout 3 takes place in 2277 (4 years before Fallout: New Vegas), this makes it impossible. Best regards, Kastera talk 18:35, March 19, 2011 (UTC)
And Rex is simply a common dog name. Ausir(talk) 18:37, March 19, 2011 (UTC)
Very super common, if you lose Rex in FO3 and have the puppies perk, the "new" dog you get is *gasps* Rex.
That's Dogmeat, the Fallout 3 version, not Rex. NatsumeAshikaga (talk) 22:56, August 31, 2020 (UTC)


Just added some information regarding Rex's breed in the notes section, if it isn't relevant feel free to delete it. --Cartman! 23:48, April 11, 2011 (UTC)

Say, what breed of dog is Rex?--Cyberweasel89 19:39, October 4, 2011 (UTC)

He's a German Shepherd

he was mean't to be a diffent breed a goldish-blacky sort of colour but eventually that bwas cut from the game.

Brains are quest items

I was wondering if you have all three brains will the one you use be the only one that is removed? I don't want quest items clogging up my inventory because they cant be dropped (i play on xbox so no console commands) God damn ghouls 18:02, June 23, 2011 (UTC)

Inventory Crash

Earlier on in the game, shortly after I gave Rex Rey's brain, I dumped much of my inventory so I could begin the Honest Hearts add on, and later on, (at level 25 with most quests completed), I returned to Rex at The King's School, and attempted to get all my stuff back. I took most of it, but when I got to the shovel, My Xbox froze, and no solution attempted worked. (Placing extra items in and taking them out, placing extra items in and moving from item category, hoping to pass the shovel.) Also, from the limited items I could view from taking the rest before the shovel, I noticed a Survivalist's Rifle with an unknown mod on it. (Had not accessed his inventory since BEFORE Honest Hearts.) Does anyone know a solution?

Multiple Companions?

I know Veronica has a bug to get all the companions on your party simeautaneously, but is there a bug/glitch or a mod to allow you to field both Rex and EDE at the same time?  :?

Health Points

It's saying 400 maximum HP on the stats screen, but Rex is on 600HP. Roundabouts. I got him Lupa's brain.. I can get photos and videos if proof is needed. I'm on xbox 360. --CDEagle147A "jesus cripes theres a thousand pigs!!" 04:07, September 25, 2011 (UTC)

Big Boom When Rex gets unconscious

Sometimes when Rex is knocked unconscious there's a big boom like as if Rex shot a Fatman mini nuke at the people were fighting. Has this happened to anyone else, please let me know.

Subtle Ambient barking?

I'm not sure if this has already been noticed or not, but ever since Rex has been a companion the ambience background music starts playing distorted, kind of "squeaky" barking noises. Is anyone else getting this? -- 23:58, March 5, 2012 (UTC)

i dismissed rex before i started old world blues and i have searched the king and his building several times as well as the entire freeside area and he is no where to be found

Rex Damage Stats

The infobox lists Rex's damage as 40 upgradeable to 100. Where is this information from?

In GECK, he is listed as having damage 30. There is a Rexbite weapon, but it is not used in game. It is listed in the weapons Rex is allowed to use, but the actual weapon isn't on Rex, and the only places the weapon exists are in the walls of the Lucky 38 suite. --One eyebrow priest (talk) 06:52, September 10, 2012 (UTC)

Followup Edit: After a lot of research, I have obtained the actual damage stats from the game. You have to use getavinfo unarmed damage. getav does not work, because that gets you the unarmeddamage modifier which is ignored on creatures. Rex's base damage is 30+level. He scales at .75 of the player's level up to 40. So his min damage is 38, max damage is 70. If you choose Rey's brain for him, he gets a +25 damage bonus from the Rexbiteknockdown script. The weapon "Rexbite" does absolutely nothing as far as I can tell.--One eyebrow priest (talk) 08:49, September 10, 2012 (UTC)


After getting a new brain for Rex, I sent him home ("Rex has returned to Freeside") but now I can't find him again. Shouldn't he be with the Kings? 18:43, September 27, 2012 (UTC)

Rex sometimes doesn't follow requiring you to go back and find him

Rex sometimes just sits at the last place I was with him, for example, raising the bomber out of lake Meade. I didn't tell him to wait, and Boone follows me, but when I went to have a look a few hundred meters away, only Boone is with me. Looked on the map and Rex is sitting at the last place the three of us were (sharp shooting lake lurks from the shore). I have to go back and find him and then tell him to wait, then follow me. After this he will follow as normal, and have had a couple of instances where both Boone and Rex are just standing where I was 10 minutes previously. It's happened around Red Rock Canyon and other various locations. Has anyone else had this issue? ~~Alice~~


I have no evidence of this, but I always thought that the dogs named Rex in Fallout New Vegas and Fallout 3 were a reference to one of the first things you encounter in the 1988 game Wasteland, which of course was an inspiration for Fallout. A kid named Bobby has a rabid dog called Rex which you have to kill as part of a quest. Of course, Rex is a very generic dog name, so it may just be coincidence, but I thought that was a continuing theme and reference. 16:37, April 6, 2014 (UTC)

Caesar's Companion

Can someone give me the reference to where it strictly says that rex was caesars companion? I mean, if you take Rex with you to Caesar, the man doesn't mention a damn thing so where's the proof? Gunslinger470/The-Gunslinger "Some say this user is a Moderator..." Some say this user used to be a Moderator... 03:18, May 10, 2014 (UTC)

When you talk to Rex, choose 'I want to take a closer look at you,' then 'Examine the painting of the bull on Rex's side.' It then says, 'The paint, though weathered and fading, is still a recent addition to Rex's bodywork.' The bull is the symbol of Caesar's Legion.

Also, if you give Lupa's brain (the legion dog) to Rex, Rex's ending says, "Rex gained all of the donor's experiences traveling with the Legion. These melded well with his own memories of the Legion, and his new mind quickly adjusted to the myriad memories" 17:14, February 19, 2016 (UTC)

Brain changing

Isn't it rather odd that changing rex brain he still counts as rex? wouldn't giving him Lupa's, violet's or so on's brains make him that dog instead? It doesn't make sense. The body is the same, yeah, but it's still a different dog.

Yeah but since hes a cyborg dog his old memories were downloaded in to a chip most likely.