No Gods, No Masters

No Gods, No Masters is an achievement/trophy and final main quest in Fallout: New Vegas if the Courier chooses to ignore the 3 other main factions (NCR, Caesar's Legion, and Mr. House) and go it alone, by using Yes Man to help them to fight for an independent New Vegas. Ensure that one has gone to the underground bunker and upgraded the Securitron Army prior to talking to Yes Man at the conclusion of Wild Card: Finishing Touches.

Synopsis
It all comes down to this: Yes Man's Securitron army will take Hoover Dam and the Courier shall establish themself as the de-facto ruler of a fully independent New Vegas Strip.

Detailed walkthrough
After telling Yes Man that the player character is ready to go to the dam, they will start this quest on the western end of the dam with a Securitron.

As the Courier walks forward they will see the large turret to their right explode and will see in front of them four or five NCR troops ducking behind sand bags while fighting the Legion. One can then sneak past them all, kill them all or kill just one side if the other is not hostile the Courier. There are several legionaries coming from the eastern side of the dam and from the drainage towers to the left as one crosses the dam. There are some NCR snipers on top of the dam towers to the right as one crosses the dam. After crossing the dam, the Courier will have to enter the last tower to the right, and use the elevator to descend to the Hoover Dam offices.

After entering the offices they will encounter two NCR heavy troopers armed with heavy incinerators burning four Legionaries cowering away from them. The player character can kill both the legionaries and the NCR troops, sneak past them, or convince the NCR troops with a Speech check of 75 during dialogue. Afterwards, install the override chip into the large terminal with several screens attached to it, at the end of the room. Yes Man will contact and inform the Courier that they have two options:
 * Activate the Securitrons underneath the bunker at Fortification Hill.
 * Deactivate the dam's power output, rendering it useless to the NCR.
 * Note: neither of these options will affect the ending you will receive. See Fallout: New Vegas endings for details.

After choosing either option the Courier will have to run through the halls, where more legionaries and NCR troops will be fighting each other. The Courier can sneak past them all, kill them all or kill just one side if the other is not hostile towards them. To get from the control room to the manual override switch, turn and follow the hall to your left after exiting the control room, then turn to the right down the next hall and go to the end of the hall and turn to the right and open the door to a balcony overlooking one of the dam's eastern plants. Turn to the right and flip the switch, then go straight down the hall where you came from and turn through the open doorway to the left, and use the elevator to ascend to a room inside one of the eastern towers. Inside the room is a staircase to the right after you come out of the elevator. The room upstairs from the elevator are some toilets, sinks, and a first aid box hanging on the wall. before continuing to cross the dam. Exit through the door to the left of the elevator if the elevator is behind the Courier.

As the Courier crosses to the eastern end of the dam they will see fires burning at Fortification Hill, if they decided to activate the Securitron army. Several more legionaries will be coming from the power output towers to the left and from the eastern end of the dam and they may try to take cover behind the sand bags, there are also some NCR snipers on top of the towers, including the tower the Courier came out of. If one completed the quest Volare! and helped the Boomers, they will fly the restored B-29 over the dam and bomb a number of the legion. If you completed the quest For Auld Lang Syne and told the Enclave Remnants to assist the NCR against the Legion, they will fight by the Courier's side, if the NCR is not hostile towards the player character, but if the NCR is hostile then Cannibal Johnson will attack the Courier making it very likely that one will have to kill them all, except Daisy Whitman who flies away inside the Enclave Vertibird. If one decided to activate the Securitron army, then they will have several Securitrons to assist them in the battle. After crossing to the eastern end of the dam, one will have to cross the bridge to the right and follow the path to the gate leading to the legate's camp. The path has more legionnaires coming from the legate's camp to kill or sneak past.

Follow the path down the hill from the gate and enter the legate's camp to the right. Inside the legate camp are some praetorian guards and some other legionaries to kill or sneak past. Go up the hill to meet Lanius and either kill him and his legionaries in a duel, or convince him to surrender with numerous Speech checks of 55, 65, 75, 85 and 100. The Barter check will ultimately result in combat. After making either decision, go back to the gate at the camp entrance and the Courier will be confronted by General Oliver, six NCR Veteran Rangers. The Courier has the choice to kill them, convince the NCR to leave, or to throw Oliver off the Hoover Dam.

Behind the scenes

 * The phrase's origins date back to the late 19th century France, where it was coined by the socialist Auguste Blanqui. "Ni dieu, ni maître" -- "neither God, nor master." Since then, the phrase has been used by anarchists.


 * If one is listening to the NCR Emergency Radio during the final battle for Hoover Dam, among the battle chatter about positioning snipers and reinforcing positions one may hear the lines "They're coming out of the walls man! They're coming outta the damn walls!" and "Game over man! GAME OVER!" This is a reference to Bill Paxton's character Private First Class William Hudson from the film Aliens.
 * The voice will also reference Doctor Who, with location Bravo Bravo Charlie (BBC) being mentioned just before saying "The Doctor is coming", and Lost, by telling 4 to reinforce 8, 15 to reinforce 16, and 23 to await reinforcement by 42.

Bugs

 * After the player character receives the briefing from Yes Man about what needs to be done at Hoover Dam, the game presents a pop-up warning about moving into the endgame. If one doe not say that they want to move on to the end of the game, and leave New Vegas, this quest will not load and the gate to enter New Vegas will be locked, preventing them from getting back into the Lucky 38. A fix to get back into The Vegas Strip is to pull-up the console with the "~" key, click on the door to select it and type "unlock". This unlocks the gate and allows the Courier to continue.
 * If the player character chooses to run back out of the gate before facing the Legate, they can fast travel from the area. Doing so causes the Courier to be unable to fast travel from another location. This can be dealt with by walking into a building and back out, but this must do this every time to continue fast traveling.
 * Game always crashed to desktop when engaging the first Legion soldiers. After leaving Boone inside the first building and engaging the legion alone, the game worked properly.
 * After telling Yes Man that the Courier is ready to go to the dam and if you have ED-E as a companion, ED-E will stay in the same spot where one starts at, as no companions are allowed into the Lucky 38 penthouse, so he will stay in wait mode as he was left as in the floor he was in. To fix this one will have to open the companion wheel and tell ED-E to stay, afterwards tell ED-E to follow the player character.
 * - Xbox/PS3 unconfirmed. "East Power Electrical Switch". Before attempting the mission it is possible to activate this switch so when the player character is on the actual mission there are no interactions with it available. Simply continue and "Exit out to the east side of the Dam". This step in the quest log will remain uncompleted but will not affect the outcome. When confronting General Oliver the securitron army will still appear.
 * If one kills Legate Lanius by a sneak attack critical from afar the quest log will still tell the player character to deal with him, making it impossible to complete the quest. (Killing every legionary in the area and exiting through the gate will make the quest go on as it is supposed to.)