Veni, Vidi, Vici

Veni, Vidi, Vici is the final main quest in Fallout: New Vegas if you choose to side with Caesar's Legion.

Detailed walkthrough
First, to initiate the quest, the player must have finished Arizona Killer quest and by then have access to start "Veni, Vidi, Vici" (which is a final test that results the Legion attaining victory and control of the dam and New Vegas with the rest of the Mojave). You will start off in Legate's camp, in Legate's war tent where Lanius will open conversation with the Courier, before the attack on the dam. After the conversation with Lanius, the Courier will be summoned outside the tent where he will witness dozens of legionaries preparing to attack and then march towards Hoover Dam. The Courier must then follow the path of the legionaries, past the gate from the Legate's camp to the dam.

On the last section where the Courier is confronting General Oliver, there are many soldiers, the Courier must choose to either fight or cause Lee to leave with 100 Speech. If you choose fight, first of all, the Courier must make their way around the force fields. After you do this, proceed to the second level. On this level, the general's guards must be killed, but keep an eye out for the many traps. Both corners of the office room on the 2nd floor have frag mines concealed in them that cannot be disarmed; the middle office sections are full of rigged shotguns and high damage explosives. Furthermore, some of the guards here have been known to carry anti-materiel rifles, which can greatly complicate matters for an unprepared Courier. After killing the guards, proceed to kill the general. Leave the room and be congratulated for spilling blood by the Legate and the game will end.

Behind the scenes

 * "Veni, vidi, vici" is Latin for "I came, I saw, I conquered," and was Julius Caesar's description of the short Battle of Zela that he fought against Pharnaces II of Pontus.
 * If Arcade Gannon is following as a companion, he will leave upon arriving at the Legate's camp. Attempting to talk to him again will result in him saying "Why don't you make like Odysseus and get lost?" This is a reference to Homer's "The Odyssey" in which Odysseus treks 10 years across the Aegean Sea, trying to return to his home island of Ithaca following the Trojan War, but gets lost and side-tracked numerous times along the way.

Bugs

 * After leaving the Legate's tent, the gate to the dam will not open and you are unable to fast travel thus you are unable to complete the Veni Vidi Vinci quest and finish the game.
 * When entering the Hoover Dam area with Rex and Cass or Rex and Lily as companions, both automatically go unconscious.
 * Raul randomly dies when attempting to enter Hoover Dam from the Legate's Camp. Waiting for an hour as soon as you walk through the door may prevent this.
 * The terminal to release the Legion Centurions inside the Hoover Dam Intake Tower 01 may not appear.
 * If you choose to wait before entering legates camp, you might not be brought to the camp when you finally choose to go. Instead it will simply bring up the prompt, and then not do anything after choosing "yes".
 * After talking to Legate Lanius, the screen will fade to black, but instead of the player exiting Lanius' war tent, the player remains inside, unable to move or interact with the world, making it impossible to complete the quest.
 * During the confrontation with General Oliver, after killing him and all his guards the quest will not move on to tell you to exit the room. Despite searching every area for any lingering enemies no red tick(s) will appear. Simply load a save from before the conversation with General Oliver and try again.
 * After killing General Oliver and the rest of his troops, the game will prompt you to exit through the first floor. The game may freeze (leaving you inside the room) when activating the door.
 * During the confrontation with Oliver and his troops the player must navigate through a room full of mines, tripwires, and other traps. If the player quicksaves and quickloads all the mines previously detonated will detonate again.
 * It is possible for an NCR ranger to become friendly in the office trap area. They will flee from the player, making the objective of killing all NCR soldiers much more difficult.

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