Hecurn

Location
is the Mystery Merchant you will find in various locations around Helkan District.
 * Zulfikar Fortress, next to Shariar merchants
 * Khanovar Citadel
 * Cyanocannon Foundry, north edge of the southern platform
 * entrance of cave/road leading to Argonea
 * Peril Cavern camp, inside Argon Valgurati Stronghold
 * last southern room in east inside of Valgurati Stronghold
 * eastern end of Argon Bulwark (MM discord)
 * hidden inside vehicle west of Carnage Vale (MM discord)

Mystery Merchant Shop
's shop information can be found in this list here

Trivia
The only Difference in the all of Arborea's Goblin merchants in the color of their backpack. has a what color Backpack?