There are many important characters in this game other than Gordon Freeman. Some are Eli Vance, who worked at Black Mesa with Gordon Freeman before the Combine came. He is part of the resistance. Alyx Vance is Eli's daughter. She travels with Gordon in part of the game. Doctor Mossman also worked at Black Mesa. She works with the resistance, but is also a traitor who helps Doctor Breen. Barney Calhoun was a guard at Black Mesa. Now he leads the resistance.