Armor Merchant is a dwarven merchant and also a member of the Merchant caste located in Orzammar Diamond Quarter during the Dwarf Noble Origin. As his name suggests, he is mostly selling dwarven armor as well as Metal Shards.
This merchant was one of those who auctioned permits to sell their wares in the Diamond Quarter as part of the festivities for the nomination of King Endrin Aeducan's middle son/daughter as the new commander.
When the Dwarf Noble talks to the Armor Merchant, he says how honored he is that his/her Highness visits him and admits that his wares cannot be matched with the amazing Aeducan armor that the Dwarf Noble is wearing but if he/she is interested he could present his wares. However, Gorim disrupts him, saying that he knows very well that the House Aeducan has its own royal armorers, to which the merchant quickly apologizes. If the Dwarf Noble pursues for more information regarding his wares, he will mention that he personally purchases the best iron ore and oversees the armor's crafting by the most skillful of the Smith caste. Regardless of dialogue choice, however, the Dwarf Noble can afterwards take a look at his wares.