Vargas was born in 2247. The sergeant of Lyon's Pride, Vargas is 30, and a no-nonsense, professional type. He is Sarah's right hand man; she relies on him for his experience and advice, and he supports and mentors her. There is a very close but mostly unspoken friendship between them.
He is initially encountered patrolling the lobby of the Galaxy News Radio building. After completing the Following in His Footsteps quest he can be seen patrolling the Citadel. When traveling across the bridge during the quest Take it Back!, Vargas will usually be killed and if so will no longer be present in the game.
If you skip the Galaxy News Radio part of the main quest and go directly to Rivet City to talk to Dr. Li, and continue from there with the rest of the main quest, Paladin Vargas will be marked essential during Take it Back!.