Theo

Theo was a member of Reilly's Rangers, a mercenary group operating in the Capital Wasteland. You find his body in the Statesman Hotel. It is revealed by Reilly that he was killed by a stray Frag Grenade as they ran to the top floor, and that he was carrying their ammunition. You can only take the ammunition if you have the code that Reilly gives you. If you take the ammo, you can keep it for yourself or distribute it to the other members of Reilly's Rangers.

It is revealed by accessing Reilly's private terminal that Theo was on a temporary contract to the Rangers, and that this mission would be the deciding factor as to whether he joined the group as a permanent member. His role before his death was mainly helping out around the base and transporting ammunition.