Who is your arch enemy in new vegas and why it become your arch enemy????

Legion.... cuz they suck Slavery ? No on my watch they can go back with they dresses back to Arizona I see them I shoot them there is nothing simple as that

I have a mod that adds in a lot of hard npcs (ive forgotten the name) and one of the npcs it adds is called Dr death, which suits him perfectly because every play through I go through I get insta killed a mile away because he has an extremely powerful 50 caliber sniper rifle. Hes also surrounded by tons of raiders so hes hard to spot. So Dr death is my arch enemy.

Zombie stromtroopers... thanks rex.....

So many attempts failed to kill them.... so many dead companions

zombie storm troopers like luka said i have no companions now

Cazaclaws, I downloaded the mod.......installed it....and ill never forget........who ever made that mod should be put in a asylum.

Considering the lore, Ulysses is the most befitting title of arch enemy in the game. I always love the DLCs of New Vegas because all DLCs connecting to each other and in the end, pointing you (If you play in order that is) toward the edge of divide. In there, you meet your Ulysses and have the ultimate showdown. The whole story is just so rich. I wish Bethesda can learn this from Obsidian.

Honestly, my arch enemies are split into three categories. With mods, without mods, and TTW (with mods)
Vanilla game
Vanilla game has to be Elijah. Why not Benny? Why not Ulysses? Allow me to explain:

Benny:

Ulysses:

Elijah my true foe.:

With Mods
Marko. Has got to be Marko. The legend of the man, the mystic, the pure unadulterated evil that he is, makes him my enemy. The man so well put together, and takes so much from you that you just want to see him dead. But even that will only grant you the satisfaction of knowing he is gone. Because Marko

NVB SPOILER:

TTW with Mods
As annoying as this response must be at this point due to its lenght. We have come to its end. The arch enemy in TTW is none other than Colonel Autumn. I dont care about letting him live, I dont care about what my father would have wanted. That man was dead the second he set foot in the memorial. His smooth accent, and carefree arrogent attitude always has me waiting for the moment its just me and him, and a gun.

With the inheritance installed id said Esther....

Many people know why.

And dammit my name is also Marko with a K...

Marko was a killer enemy. I had a tough time with him.

I actually like the absence of a true arch enemy in New Vegas. Everybody is trying to play for their own interests, all of them with understandable motives, so it's not black-and-white who you choose to side with, they're all "win some, lose some" and you have to think about your priorities.

Like with Benny, you just happened to be between him and his plan. It was nothing personal.

@ZombieRedNeck put it quite well

I never really thought about who my arch enemy is in New Vegas. I suppose if i were going to choose one, i would probably have to say Father Elijah and agree with ZombieRedNeck on this one. He really is the worst person in the whole base game i think. I hated that bomb collar.

NCR and Caesar's Legion. They have put a price on my head, and they send their men to kill me. Each time I'm in the wasteland, I meet with like 5 of NCR's or like 5 or 6 from the Legion.

Benny OFC, and Dr Klein how i hated that talking scrap that acts like Human was made by robots.......

Father Elijah, for what he did to Christina.How much pain, how much suffering it brought, this cute girl ...
Who's must-was to stop him, this psychopath.I did not close it in the store, it was clear that he would find a way to get away from there.By this, we met in person, and I did everything with his hands, as the same as you did to Vilis...
Shot in the head, to be sure of ...

@BeSPrideL
You and me believe in the same enemy. However, I believe him to be the only evil in the Mojave. Not just for the lovely christine, but for his overall plan

@ZombieRedNeck
I also think that he was a threat throughout the Mojave.
What was previously written in these lines-Who's must-was to stop him, this psychopath.I did not close it in the store, it was clear that he would find a way to get away from there.By this, we met in person, and I did everything with his hands, as the same as you did to Vilis...
But he was not the only one threatened Mojave.
P.S.
I am happy that we have one opinion about Elijah)

Easy Pete. Through all the weapon, armor, and race testing I've done, in Goodsprings, he is bound to end up throwing dynamite, or filling me with .357 ammunition at some point. I should consider adding him as final boss somewhere in the World of Pain mod. Would be fitting to have him as a regular nemesis. :S

For me it's myself....Err lilith she hunts me down every three days hehe I hate it sometimes.
Un-modded Klein was quite annoying as well as House but Mr. House you see I got everyone to play nice .... Kill them anyway but..but I like the BOS At the same time I respect house more than anyone in the entire game

@me444 all weird fetishs aside, I agree that house has the best overall intentions of the three. NCR will just move on after hoarding all the resources...and we dont even need to get into what the legion does. House is in fact the most admirable of the lot. Which is why I take no pleasure in killing him everytime. All hail the king baby

Cazadores they are the scariest enemy in fallout NV who the hell thought giant wasps were a good idea fuck you Dr.Borous.