Sent to New Vegas four years before the start of the NCR-Legion War, Curtis joined the New California Republic Army and rose to the rank of captain in three and a half years. He mentions that the process normally takes four years, though he sped it along by arranging an "accident" for an existing captain, creating an "early vacancy" that Curtis proceeded to fill. A member of Colonel James Hsu's staff at Camp McCarran in 2281, Curtis serves Caesar's Legion as one of its most valuable spies in the Mojave. Given considerable trust by the NCR, Curtis has used his post to sabotage NCR operations and increase NCR casualties by reporting plans and troop movements to the Legion over radio.
If the player character sides with Caesar's Legion, Vulpes Inculta sends the Courier to Camp McCarran incognito, where they assist Curtis in destroying the McCarran-Vegas monorail and help him avoid detection by killing Private Davey Crenshaw and planting incriminating evidence in his footlocker. Instead of disappearing from the NCR Army after the bombing like he had originally planned, Curtis decides to stay and develop his role into "something grander," enabling him to greatly benefit the Legion for a long time to come.
Alternately, if the Courier has killed Private Davey Crenshaw prior to working with Curtis to bomb the monorail, Curtis is unable to find a proper scapegoat once the bombing happens. Curtis recognizes that without someone else to blame, the NCR will sooner or later figure out it was him. He makes plans to disappear from Camp McCarran and tells the Courier that they cannot be seen together again, and will thereafter not engage in dialogue.
If the player character sides with the NCR, Curtis is found out as a spy and when confronted forces the Courier to kill him rather than be taken alive. Colonel James Hsu and through him the NCR are fully alerted to the extent and details of Curtis' treachery. His death is a disaster for Caesar's Legion, ruining Caesar's years-long effort to plant a spy at Camp McCarran.
If the player character kills Colonel James Hsu while working for Caesar's Legion, a dismayed and furious Curtis says that the Courier has set him back years in his work as a spy. Curtis spent years earning Hsu's trust, and when the NCR replaces him "within a week" Curtis will have to start all over again. He angrily banishes the player character from his sight and will not speak to them again.
His office is located on the first floor of the terminal building. It is to the right and behind of the right stairs leading up to the second floor. You'll know it's his if you see the Sniper nest location note on his desk.
If you kill Curtis and return to The Fort and talk to Caesar, he will be angry and tell you that he found out about you disarming the bomb on the monorail and killing Curtis. He will then say that because of your services, he will let you confess to all crimes you have committed against the Legion and not kill you. This is a fallacy, because when first confronted by the Legion and given the Mark of Caesar, you are told that you will not be given any other chances to redeem yourself for crimes against the Legion, so therefore Caesar went back on his own word.
Even though he is a Legion spy, he will be hostile towards you if you are Vilified with the NCR and see through any NCR disguise like a normal NCR ranger.
Killing him counts towards both the challenge Armed For Bear and Against All Tyrants; however, since the challenges use mutually exclusive lists of weapons, it is not possible to earn credit toward both challenges with a single kill.
"You're getting too close, Shamus." is a reference to the television series Carmen Sandiego. Shamus is a slang word for a private investigator.
During his radio transmission to Caesar's Legion, he calls somebody with the callsign "Lupa," identifying himself as "Picus." This refers to the she-wolf, Lupa, who nursed the infants Romulus and Remus, and Picus, the woodpecker who fed them.
ps3pc He may be the only hostile person in Camp McCarran if there is an abrupt drop in reputation with the Legion, or perhaps an abrupt increase in reputation with the NCR. - Happened after a disguise glitch.[verified]
ps3pc If Colonel Hsu is killed and one talks to Curtis, he will express his anger with the Courier for setting him back years in his mission even if the player has never spoken to Ceasar about Curtis being a spy. [verified]