Sent to New Vegas four years before the start of the NCR-Legion War, Curtis joined the NCR 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 the former captain. Using his new position, he was easily able to provide information on NCR plans and troop movements to Caesar's Legion and sabotage NCR assets.
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]