claude d'arcis

[sheronaicecube]

i have the basic access version of the game.
it says to defeat claude d'arcis, who is disguised as a sergeant in the fort at port royal.
i've been to the fort, and all the sergeants are level 12+, I'm only a level 5.
also, i noticed on all the forums here, it says he can be found in the thieve's den or the tortuga graveyard.
where is he, really??