Legate Lanius

Lanius is Caesar's Legate, living in the Mojave Wasteland in 2281. He is the final boss and the most dangerous obstacle player faces in three of four of the game's ending quests.

Background
Asking Caesar about the legate reveals that Lanius was a member of a tribe hostile to Caesar's legion and Lanius was a bloodthirsty champion of the tribe, sometimes ambushing whole groups of soldiers by himself. When Caesar's legion was attacking his tribe, they knew that they would not be able to win so they sounded the surrender alarm, driving Lanius insane with anger, resulting in beating the Chieftain to death which caused his tribe to turn hostile to him. After taking out fifteen of his tribesmen, Lanius woke up in a bed with most of his face torn off, Caesar showed him the mask he had forged for him and offered him a place in his army.

Interactions with the player character
If siding with Legion, Legate Lanius will be the one who gives the final order to the Courier, and also the one who congratulates him after the battle. In all other cases, Lanius is the final opponent.

At the battle of Hoover Dam, if against the Legion, Lanius can be convinced into surrendering with numerous Barter and Speech checks, respectively 55, 65, 75, 85 and 100. Convincing him that the vast territory of the NCR is its weakness and that the Legion will not be able to claim and hold it. It is also possible to take a different speech angle to convince him to leave, suggesting that his fight was too easy because a trap lies in wait for him, and that you are only telling him this because it would be dishonorable to defeat a foe in such a way.

It is possible to kill him in one shot before he notices you, bypassing the conversation entirely. Before he talks to you he will appear as a friendly, however. With high enough (Good) karma or speech there is an option to have him fight you alone.

Appearances
Lanius appears in Fallout: New Vegas. He serves as the final boss of the game during the final battle at Hoover Dam, unless you side with the Legion. He is carrying the Blade of the East.

Behind the Scenes

 * "Lanius" is Latin for "butcher." And "Legatus" also know as "Legate" are the generals of the Roman Empire, equivalent of the modern general officer.
 * He constantly mentions Mars, the Roman God of War, and claims that his name (Lanius) comes from the Son of Mars, being Caesar himself.
 * Strangely, while it is mentioned that his face was torn to pieces, under his mask he has no injuries.