Wagner is a salvager ghoul living in Denver. Formerly of the Necropolis, made his way north to Gecko, left Gecko after a few months. Lived as a traveler, selling supplies and working as a light mechanic/electrician to towns. Friendly-looking (big happy grin), goggles. Never sure you can quite trust him. He seems nice and friendly, though.
He is actually working for Willem Clark in the Reservation. If the radio tower is every fully operational, he'll try to send a signal. Will be surprised to see Measles if he shows up and kinda nervous (chance? Or is Willem doing a followup?).
Wagner has not appeared nor is he mentioned in any published game. He was to appear only in Van Buren, the canceled Fallout 3 by Black Isle Studios. It is not certain if he will appear in any future Fallout game.