Mex

Mex is a slaver guarding the gate to The Pitt, in the year 2277.

Daily Schedule
He stands at the Pitt's gate all the time guarding it from non-raiders and from escaping slaves.

Interactions
He will take all the items in your inventory (except the "hidden weapon" you may have received from Werhner and the Worn Slave Outfit you took from the dead slave) and then tell you to enter Downtown.

Appearances
Mex appears in The Pitt add-on for Fallout 3.

Behind the Scenes

 * Mex is most likely a reference to the chain of Mad Mex restaurants, which are relatively popular in Pittsburgh, and the surrounding area like in Monroeville and Squirrel Hill.