Chris Haversam grew up in Vault 34 and was assigned as the vault reactor engineer due to his technical aptitude (and preference for machines that don't shoot people, which made him a preferred pick over fellow engineers Houser and Mitchell.) He believed the radiation he would absorb from his many visits to the vault reactor would turn him into a ghoul, although most of the management dismissed his claims as neurotic.
Eventually, his hair began falling out due to natural reasons, but Chris insisted he was becoming a ghoul due to radiation from the Vault reactor and subsequently left the Vault. The vault descended into chaos shortly after his departure, when the reactor became unstable and began leaking dangerous radiation, turning most of the residents into actual ghouls.
Believing himself to be a ghoul, Haversam joined the Bright Brotherhood in 2279. He could not be convinced that he was a human, so Jason Bright decided to accept him into his congregation believing him to been sent by the creator to ensure the success of the "Great Journey." Bright also believes that Haversam is blessed with ignorance: both that he is not a ghoul and that he cannot join them on their journey. There is no malice in this decision, however: they would take him if they could. With his technical expertise, Chris was made the engineer in charge of the entire project to accomplish their goal.
The player character can convince Chris that he is indeed human with a Speech check (50) or with the Black Widow perk, and the rest of the Bright Brotherhood needs to leave him behind. The Courier is given the choice to help him sabotage the rockets so the ghouls die in flight. Alternatively, they can convince Chris not to sabotage the rockets, and he will send them off with no hard feelings before heading for Novac.
Chris thinks he's a ghoul, and therefore calls the Courier "smoothskin" and speaks rudely to them. He also naturally speaks in the distinct gravelly voice that is typical of ghouls.
After the quest is over, he can be found milling about Novac. If the player character talked Chris out of his hard feelings for the ghouls before the launch, but then sabotaged the controls anyway, Chris will remark that he was lucky not to have been on the rockets. If the player character admits to sabotaging the controls, Chris will yell, "You bastard! Those ghouls declared me a saint!" and then turn hostile. Though he carries a 10mm pistol, he won't fight back and will instead run away.
He can often be seen entering Manny Vargas' room in Novac, and one will occasionally find him in the room at night, which might mean that is his new place of residence.
"Oh god! You're telling me the truth, aren't you...? Oh no! How could they do this to me? For two years? My god, I've been a joke to them! Do you have any idea how easy it'd be for me to sabotage those rockets? That'd be a joke, huh? One hell of a joke!"
The following is based on unverified behind the scenes information and has not been confirmed by canon sources.
His entire story parallels that of Saint Christopher, the patron saint of travel.
Both were spared from a grisly fate by the very same religious group they aided.
Both were immortalized in religious chants by their respective religious groups.
Both were revered religious figures at the end of their stories by helping the followers of their respective religions reach a paradise in the heavens through selfless dedication and sacrifice.
His name appears to be a play on Mr. Faversham, a character from the Honeymooners of similar build and appearance. Faversham also has a tendency to be overly enthusiastic in his belief that what he feels is right has to be correct.
End of information based on unverified behind the scenes information.
PC If you convince Chris that he is human before acquiring the parts, he sometimes will have headed to Novac before you return and the quest becomes impossible to complete because the quest conversations never come up, so the parts never get delivered, and he instead thanks you for telling him about Novac.
PCPlaystation 3Xbox 360 After completing the quest without convincing him of his humanity, he may simply say "Not now, it's almost time for the Great Journey." over and over again without acknowledging the fact that they've already left without him. This can happen even if you convince him of his humanity through speech checks. If this happens, he will remain in the control room indefinitely rather than moving to Novac. In order to avoid this bug, make sure to first convince Haversam that he is human (make sure that's the first dialogue you make with him), and then it's safe to start his quests (gather thrusters and then the green substance). An alternate solution is as follows: After handing over the 2nd item and telling Haversam to start, Jason Bright will start his speech. The player MUST wait (and listen) until Jason will finish his speech. After that Haversam will run to the exit. The bug can happen even if you convince Chris he is human before starting his quests. If Jason's speech still gets cut off and Chris stays stuck in the basement, before telling Chris to initiate the rocket launch, pick the dialogue option to delay the launch instead, leave the area, wait, then speak to Chris again, this seems to fix the bug, Jason will give his full speech, then Chris will run for the exit afterward. [verified]
PCPlaystation 3Xbox 360 If Chris is killed after telling him to begin the launch, but before the launch itself, his body will appear in Novac. [verified]
Playstation 3Xbox 360 If Chris is talked to during the end of the mission "Come fly with me" Chris may walk out of the control room and fall through the floor making the mission impossible to complete. [verified]
PC While wandering around Novac you can kill him without the citizens turning hostile, even if you do it right in front of others. [verified]
PCXbox 360 At the bringing of parts quest stage, Haversam can run off up the ladder and never reappear. This happens if the player ignored respawning ghouls near the compound and entered the basement via the hatch.
↑ 1.01.1The Courier: "The radiation down there would kill you, Chris. Because you're human." Chris Haversam: "I thought we were past all that, smoothskin. But you just can't resist the chance to mess with me. Typical human. I was human once, you know. Grew up in Vault 34, northeast of here. Nice upbringing, if you like assault rifles and target practice. But oh, you prefer machines that don't shoot people? Not so nice then. Who should maintain the Vault's reactor? Houser? Mitchell? No - make it Haversam. He likes machines! Haversam won't mind getting irradiated! Haversam won't mind mutating! He's already ugly as it is! Haversam won't mind when his hair starts falling out after a few years. There's no connection, Haversam! You're neurotic!" (Chris Haversam's dialogue)
↑The Courier: "You left your Vault because you were going bald?" Chris Haversam: "Bald? You call this bald, smoothskin? I'm a monster! A monster!" (Chris Haversam's dialogue)
↑The Courier: "Hey, you're not a ghoul!" Chris Haversam: "Your pranks won't work on me, smoothskin. They won't work on Jason, either." The Courier: "Smoothskin? Your skin looks pretty smooth to me." Chris Haversam: "Stop wasting my time, smoothskin. Go waste Jason's." (Chris Haversam's dialogue)
↑The Courier: "You wouldn't trust a ghoul, would you?" Chris Haversam: "[FAILED] I see your ploy, smoothskin. I won't fall for your trap. You can plainly see that I'm a ghoul myself. You can't turn me against my flock." (Chris Haversam's dialogue)
↑The Courier: "Jason told me himself. The Great Journey is for ghouls only. You're not going." Chris Haversam: "[SUCCEEDED] Oh god! You're telling me the truth, aren't you...? Oh no! How could they do this to me? For two years? My god, I've been a joke to them! Do you have any idea how easy it'd be for me to sabotage those rockets? That'd be a joke, huh? One hell of a joke!" (Chris Haversam's dialogue)
↑The Courier: "Let's talk about Chris." Jason Bright: "After all that you have done for us, I suppose you deserve to know everything... When Chris came to us, we tried to convince him that he was human. But this only angered him. He seemed... lost. We decided to let him stay with us for a few days, over the course of which we learned that his technical skills far surpassed our own. It became clear that the creator had sent him to us, to ensure the success of the Great Journey. Equally clear was that Chris should labor in blessed ignorance of his humanity, and his inability to make the journey himself. It is no coincidence that two humans have been vital to the success of the Great Journey. It is my belief that the creator sent you and Chris to expiate the sins of your kind against mine. You are redeemers both." (Jason Bright's dialogue)
↑The Courier: "So you're going to leave Chris behind?" Jason Bright: "Such is the creator's will. Vision upon vision has shown me that, were Chris to accompany us, he would die in minutes. The radiation around the launch pad alone would kill Chris in minutes. The radioactivity of the Far Beyond is much stronger." The Courier: "You've been using Chris. It's despicable." Jason Bright: "It is the creator's will, and I must submit. There is no malice in it. We would take him with us if we could." (Jason Bright's dialogue)
↑The Courier: "What do you do here?" Chris Haversam: "I'm the flock's resident engineer. I've always been good with machines. Jason says the Great Journey would've been impossible without me. Of course, my skills aren't much use unless I have the right materials. That's where you come in." (Chris Haversam's dialogue)
↑The Courier: "Why don't they let you work down on the launch pad?" Chris Haversam: "When I joined the flock, Jason made it clear that he wanted me to supervise the repairs, not do them myself. It would be a waste of my gifts to work on just one system at a time. From up here, I've been able to supervise the entire project." (Chris Haversam's dialogue)