Freedom fighters and pranksters, copper dragons are likely to get involved in revolutions, slave revolts, and other noble causes...whether the PCs might want them to or not. Their impulsiveness when choosing causes, as well as their tendency to tarnish, make them one of the few metallic species a party might in good conscience have to fight.
Bards still sing of Verdigris, a copper dragon whose sins tarnished his wings near to turquoise after his role in the Siege of Seven Sabbaths. He still lives as a recluse, avoiding the silver dragon paladins who would bring him to justice.
Slaves fleeing Pharaoh find an ally in a copper dragon, whose skill with illusions, traps, and magical stone-sculpting soon becomes invaluable to the refugees. Unfortunately, a party of adventurers is also following the slaves, trying to bring them word of aid while outracing Pharaoh’s charioteers. Sadly, the copper’s traps and deadfalls, once set, don’t discriminate.
Most sages regard the copper dragon’s deadly joke ability to be a myth. A clan of assassins is not so sure, and seeks to wrest from a copper great wyrm the words that can kill in situations where their weapons can’t reach.
—Pathfinder Bestiary 106–107