A hero armorer is a NPC who will upgrade the armor of your heroes. The upgrade allows heroes to be displayed at the "Fellowship" monument in the Hall of Monuments. These NPCs have the words "[Hero Armor]" in their name. Once a hero has been given a new armor set, it can be freely switched with the default armor and back. Note that switching a hero's armor will not cause any runes or insignias to disappear.
Hero armorers require a trophy to craft hero armor, and each armorer requires a different trophy (see below); however, various heroes may be ineligible for an armor upgrade from some armorers, for more information see hero armor.