Lanius Legate Lanius , also known as the Monster of the East , is Caesar ' s second Legate , living in the Legate ' s Camp in 2281 . He is the final boss of " " in three of four endings and one of the main antagonists of the game . Background . Joshua Graham remarks that he did not know of Lanius during his time as Legate , indicating he was not recruited until some time after the First Battle of Hoover Dam in 2277 . Asking Caesar about him reveals that Lanius was a member of a tribe hostile to Caesar ' s Legion , the Hidebarks , and Lanius was the bloodthirsty champion of that tribe , sometimes ambushing entire groups of legionaries by himself . Caesar ' s Legion then tracked down the Hidebarks , although when they knew that they would not be able to win against Caesar , they chose to surrender . Lanius saw this act as a betrayal to the tribe and it drove him into a bloodthirsty frenzy ; killing the Chieftain and fifteen others of his own tribe single - handedly before he was knocked unconscious . When Lanius woke up , most of his face was torn off and Caesar was standing beside him . He offered Lanius a place in the Legion and a mask forged in the image of the great god Mars specifically for him . Lanius accepted Caesar ' s proposal , but in return he wanted permission to kill the survivors of his old tribe ; Caesar demanded that he only kill the adult males . Since this time , Lanius has led Caesar ' s Legion to victory over nineteen tribes and has led the conquest of Colorado . Interestingly enough , there seems to be several spoken versions of Lanius ' s origins , and he himself appears to be surrounded by myths . Lucius mentions that Lanius was already a legionary by the age of twelve , which seemingly contradicts Joshua Graham ' s comment and Caesar ' s story about him . Also , Lanius is said to be a brutal savage that hates the Legion , only leading it because of his respect for Caesar . However , he demonstrates both cunning and a certain kind of honor ; seemingly has no grudge against the Legion itself , only those disobeying orders and not willing to sacrifice themselves for the Legion . Ulysses states he is never seen without his mask and that his own slaves are struck blind so as not to look upon his face , that he is not even certain it has always been the same person without his mask . These opposing accounts show that Lanius ' s image and past is more a mythic construct within the Caesar ' s Legion than a flesh and blood man , with the truth of his past only known by Caesar . Personality . Lanius is not well - liked within the Legion , and it seems that both Caesar and Vulpes Inculta harbor doubts at his ability to lead the Legion . Caesar openly admits that he does not think Lanius is worthy of being called a " great man " and believes he has no " love " for his Legion . Vulpes is more reserved , but criticizes his blunt methods and shows quiet celebration if Caesar is saved , thus preventing Lanius from becoming the new leader of the Legion for the time being . Siri , a Legion slave , describes him as not " " a man to be crossed - especially if you are a woman . " " When spoken to , Lanius is revealed to respect honor above everything . He states that treachery should not be relied on as a tactic , and hopes that the Omertas would die after their plan to hold a coup on the New Vegas Strip failed and they were discovered , as their aid in the Second Battle would have sullied the Legion . Lanius also suspects that the Legion took too much of the Dam easily and that the Republic would not be so lax in its security if the Courier bluffs and states that there is a trap set for the Legion . He also shows a dislike for Vulpes Inculta ' s methods and he criticizes his ploys as " dishonest . " He also makes hints that he believes Vulpes is a talker , not a warrior . This shows great conflict swirling around Lanius as Caesar ' s successor and adds to the beliefs of Joshua Graham , Marcus and Mr . House that the Legion will tear itself apart in the years after Caesar ' s death . Appearances . Lanius appears in " " and is mentioned by Joshua Graham in " Honest Hearts " and Ulysses in " Lonesome Road " .