Enclosed you'll find the coordinates to the military weapons cache that was uncovered in Hamilton's Hideaway. We installed locks on everything we could in there to make sure it stays in our hands. Use it in good health my man, and keep up the good fight!”
Copperhead's dialogue makes the Good Fight sound like an actual organization. This makes Three Dog's banter less of a motivational speech and more of a recruitment campaign.
Copperhead is a member of the Good Fight, and personally knows Three Dog.
Copperhead is mentioned only in Fallout 3.