With its updated reputation system, many players question if worrying about karma is even necessary. Does karma even matter in Fallout: New Vegas?
Karma does not really matter in Fallout: New Vegas. The game uses a reputation system which affects how NPCs interact with you. Karma is not nearly as serious as it was in Fallout 3.
You can be evil and still work for the NCR, and you can be good and still work for Caesar’s Legion. Only a few followers will comment on your karma, but overall, it barely matters.
If karma matters in Fallout: New Vegas
Karma does not matter the same way in Fallout: New Vegas that it does in Fallout 3. The third game in the franchise does not have a reputation system, so it relies heavily on karma.
In Fallout 3, your karma attracts groups of mercenaries who attack you on sight. Good karma players must worry about the Talon Company Mercs, and Evil karma players must worry about the Regulators.
New Vegas, on the other hand, does not have mercenaries who hunt you based on karma level. Instead, “hit squads” from enemy factions that you have a low reputation with will attack you.
Cass is the only companion that will react if you have negative karma. The rest only care about your standing with their preferred faction. For example, Boone will become vocal and leave if you’re hurting the NCR or siding with The Legion too much.
Veronica will also leave if your reputation with the Brotherhood of Steel plummets too low.
The factions themselves will not treat you any differently if your karma doesn’t match their ideology. You’re welcome to be as evil as you want and still side with the NCR. Oppositely, you’re welcome to be as good as you want and still join Caesar’s Legion.
So that’s the answer. Karma does not really matter in Fallout: New Vegas. The game uses a reputation system.