Viper gunslingers in Fallout: New Vegas
The Vipers are a band of raider-tribal with a profound shamanistic nature. They originated from Vault 15 with two other raider groups (Khans and Jackals). From Kilian Darkwater dialogue, their main base called The Shrine in 2161 was located north from Junktown but this place was cut for the final version of the game and they only appeared in-game in Fallout: New Vegas in 2281.
They are mysterious followers of an ancient religion. They usually only come out at night to hunt for food or to conduct raids. They are very ruthless when it comes to combat. They prefer stealth to strength. They used to carry bone knives and bone spears dipped in pit viper venom (this poison, when in the blood stream, paralyzes the victim) and dressed in bone armor with a red sash. This armor, as the name implies, is made from strips of bone bundled around the body with strips of leather. Most victims captured with their poison are taken back to their hideout.
The leaders of the Vipers conducts their ceremonies and administration duties. The members of the Viper will follow his orders even if it means death. The Great Snakekeeper was usually in the same type of bone armor as the others, save he wears a snake skull as a helmet adorned with feathers and snakeskin as a cape. Formerly, all viper members have crude tattoos all over their bodies (exotic piercings are not uncommon) and their elite warriors were called the Crimson Tongue.
Once a month, the Vipers fall into a deep trance through a dangerous mixture of alcohol and snake venom. Anyone who doesn't wake is considered to have been found unworthy by the Great Snake. When the Vipers reach manhood, they are given a special mixture of the pit viper venom. Those who die (or are in a coma for more than seven nights) are given as sacrifices to the Children (the snakes in the pit are officially called the Children of the Great Snake). Those who survive the week-long delirium become Warriors of the Snake (also called Chosen Ones).
There is also a monthly ritual, where the Venom is taken by the High Priests and Priestesses of the tribe in small quantities, which causes bizarre dreams. This is called the Time of the Summoning, because many claim to see the Great Snake come to them in their dreams. When it is time for a captured prisoner to be sacrificed, he is typically hurled into a pit at midnight.
Another ritual of the Vipers practiced was to capture victims for sacrifice to their god by throwing their victims into an arena with a giant pit-viper. Those who survived their encounter with the pit-viper are then granted a choice between sacrifice to the Viper's god, or to be one of the clan. For those who choose to be part of the clan had to complete a task in favor of the tribe such as hijacking a caravan for supplies, raiding a settlement, clearing a radscorpion nest, or retaking a water source from an enemy tribe. In the end, if the victim did well enough, the Vipers would accept their captured victim as one of the tribe and have their undying respect.
In 2097, Jonathan Faust, leading a group of two hundred people, left the overcrowded Vault 15 to brave the horrors of the wasteland. This relatively small band came to a small oasis in the middle of the desert. In the middle of this oasis was a large pit, almost like a crater. While resting and setting up camp, Faust decided to look into the pit.
When a member of the band called out to him, Faust turned, startled, and slipped into the Pit. He slid down twenty feet and then fell another 20 and broke his leg in the process. As he lay there dazed, a half dozen gigantic Pit Vipers slithered toward him. Not knowing what these things were, Faust was terrified. The group above heard one loud scream and then nothing. Three others went to look for him, but never came out.
The small band, leaderless and stuck in the desert with no food and water, decided to stay at the oasis, at least for a little while. They covered the pit with a tarp and nailed spikes around it to keep whatever horror lived there encased there. They then set up their camp as far from the Pit as possible. Whatever was down in the Pit never bothered them.
Days passed. The more influential of the group argued about what they were to do. There was talk of joining up with others from the vault. There was talk about going back to Vault 15.
 The Vipers
During these four days, almost all of the group was either dying or already dead. Those who survived the radiation poisoning were too weak to travel, while those who survived either left or stayed and helped defend the little settlement against the desert creatures.
Finally, after a week, the remaining members of the group decided to move on. They started to pack their belongings when an almost spectral figure emerged from the shadows. It was Faust, except this was not the strong leader they remembered. He was wan, pale, and emaciated, and there was a feverish gleam in his eyes. He told them that when he was down in the pit, a god visited him and told him the True Way. They would make sacrifices to the Gods of the Pit, and wealth and happiness would be theirs.
Of course, everyone was skeptical. Some were even violently rebellious, saying that Faust was crazy. After Faust patiently listened to them, he then whistled, and from behind him, came two very large pit vipers. Without warning, they struck. They attacked everyone in the group, including Faust, but he just laughed as they bit his flesh.
As the sun rose the next day, the two snakes lay dead by Faust's hands. Half of his people were dead, the other half were on the brink of death as the Pit Venom started to sink into their systems. By that afternoon most would be dead, but the forty or so survivors of the venom were half crazy with the aftereffects of the venom. Faust, himself immune to the venom, helped the remaining few through this time, which has come to be known as the Great Awakening. He whispered things to them, told them how the Great Snake has spared their lives, so that they would fight for his mighty cause.
And thus the Viper clan was born. They decided to make the Pit their main base named The Shrine, and to go out into the wastes and take what they needed from those blasphemers that did not follow the Winding Way of the Great Snake.
In 2125 they attempted to raid the Hub, a settlement in its formative years. However, thanks to a coordinated effort led by its leader Angus, they were defeated. The surviving members retreated to the north, roaming the wastes for many, many years, occasionally attacking caravans and small settlements.
When Faust (or the Great Snakekeeper, as he was called), grew too old to rule, his son, Asp, was given the sacred role of leader and High Priest. Around the early 2150s, however, the Vipers had grown to their former strength from captured slaves and caravan drivers and had begun to establish a power base in the badlands to the North of the Hub (and south of the Lost Hills bunker). Driven by a religious frenzy (and the need to provide for their much larger numbers of soldiers and disciples), they began raiding more frequently than before, attracting the attention of the Brotherhood of Steel. The Brotherhood sent out a few squads of scouts to track the raiders down - it was more of a training exercise conducted by John Maxson's father, as the Brotherhood was convinced that small detachment of troops in power armor would be sufficient to deal with a group of raiders, no matter how large.
One Brotherhood squad found the Vipers, and during the firefight, John Maxson's father (who was leading the squad) was killed with a poisoned arrow. The response from the Brotherhood was immediate. The Paladins, now led by Rhombus, began a full scale campaign against the Vipers, tracking them down and wiping out almost all of their members within the span of a month. A handful of Vipers were able to flee north and east into the mountain range. Most of them fled eastwards, but some stayed in California until they were almost entirely wiped out after 2162.
During the campaign, the Brotherhood of Steel sent a few scouts and emissaries to the Hub to track down Vipers members, and from these beginnings, the Hub and the Brotherhood of Steel began full trade relations (caravans had delivered to the Brotherhood before, but not long after the destruction of the Vipers, caravan trains ran directly from the Hub to the Brotherhood on a regular basis).
 Hounds of Hecate
|The following is based on Van Buren and has not been confirmed by canon sources.|
Some of the Vipers who fled to the east eventually came into the American southwest, and became a part of the fanatical tribal army of Hecate, a mad tribal goddess. The "Hounds of Hecate", as they were now called, served as Hecate's fist against the other tribal and raider clans in the area. They had still learned a lesson with the Brotherhood about fighting guys with shiny armor and big guns, though, and so didn't attack caravans heading between Denver and Hoover Dam, despite Hecate's wishes. They also have pet Two-headed Rattlesnakes which they raise in the canyons. Once they are old enough, they are released into the wild.
|End of information based on Van Buren.|
 Mojave Wasteland
Other remains of the Vipers have traveled to the Mojave Wasteland. Known as Viper gunslingers, they have been reduced to petty raiders by the constant attacks from the Brotherhood of Steel and NCR in 2281. They tend to be equipped with varying armor and equipment, though there will usually only be one in any given group armed with a gun. Even those that do carry guns usually just have 10mm pistols. They continued the traditional work and customs of the Vipers, continuing pillage and usually come in large groups. Vipers will usually ambush wastelanders while looting unmarked locations around the Mojave Wasteland. All of their equipment is in poor condition, but a small minority carry varying body armors, such as metal armor. They may also occasionally wear Merc outfit Generally, they are inefficient and practically disabled by their poor state of affairs. However, at higher levels, they carry grenade rifles and ammunition. Viper gunslingers and Viper leaders can consistently be found at locations such as Horowitz Farmstead, Highway 95 Viper's Encampment, and Raided Farmstead, as well as on the road leading from Wolfhorn Ranch to Nipton. There is an unmarked Viper gang camp south-east of the Hidden supply cave, with at least 4 to 5 Viper gang members present. They respawn in these locations if killed.
There were originally going to be two other raider tribes in addition to the Khans—the Vipers and some other group the Jackals. We had this idea worked out for the Vipers being in a cleft in a canyon with some beat-up wagons or motor homes, and a sort of snake-worship-cult thing going on. There was gonna be a quest where you could become an honorary Viper and go through their pit of serpents and gain the Snakeater perk for free. Sadly, we just didn't have time to actually build the map.”— Jess Heinig
They are also mentioned in Fallout 3, in the Citadel of the Capital Wasteland Brotherhood of Steel. A computer containing information about Maxson family reveals that western Brotherhood were fighting this raider group before the encounter with the Master. Maxson II, father of John Maxson, was killed by them.
 Behind the scenes
- In the Fallout Bible, Chris Avellone says that after the remaining Vipers fled to the mountains, they were never heard from again. This cannot be regarded as canon, as they were mentioned in Fallout as still being around in 2161, even if they don't appear in the game itself.
- The Vipers' camp location in Fallout's game files (accessible by CTRL-R function) consists of only 3 tents.
A part of The Shrine, the cut content Vipers base of Fallout
The information here is based on Brian Freyermuth's Vipers design document, timeline from Fallout Bible 3 and on Avellone's expanded background for the Vipers from Fallout Bible 6, adapted for consistence with the Fallout universe and their appearance in Fallout: New Vegas.