Hitman

A Hitman is a member of a four man squad of assassins hired to ambush and kill the player. They come in two varieties and appear for two different reasons. When the conditions are met the squads appear as random encounters only at certain areas of the map, usually when coming out of a sewer into the Wasteland or when Fast Traveling to an unpopulated location.

One type of squad appears only if the player has disarmed the bomb in Megaton. These Hitmen appear as Talon Company Mercenaries, complete with armor and weaponry and are leveled to challenge the player. They greet the player with a threat, cannot be bargained with, and then open fire. They carry a "Contract for Extermination" signed by "Burke" (whether dead or alive). Evil characters who arm and detonate the bomb in Megaton will have analogous encounters with Regulators. Similar Hitmen who do not carry notes may appear as a random encounter to players who have good Karma, have reached level 6 and do not have the Contract Killer Perk.

A second squad of Hitmen can appear randomly in ambush similar to the previous type once the player has completed the Strictly Business quest. These Hitmen appear as leveled Wastelanders, greet the player as "Slaver scum," and then attack. These Hitmen carry the Contract Killing note demanding "Wasteland justice." A random encounter with Slavers asking about escaped slaves is not related to the Strictly Business quest.

It should be noted that squads of two, three, or four Talon Company Mercenaries, not named "Hitman", and Regulators appear randomly to attack those with good Karma or evil Karma regardless of other conditions, and these squads carry a different note, titled "Private Contract" that includes the character's name. Neutral Karma characters have reported encountering both groups, sometimes at the same time.

Trivia
Hitman is the name of a famous videogame about an assasin.