Install DLC on your platform - visit suitable for your platform shop (Origin for PC, Xbox Store for Xbox One and Xbox 360, PlayStation Store for PS4 and PS3)
In game, you have to be log in to your store account, for PC log in to Dragon Age Servers to update game content.
Check War Table for The Black Emporium Operation (cost:0). Complete it and get there.
NPC: Xenon the Antiquarian
I left the Black Emporium empty-handed for two reasons. First: most of the items were priced far beyond what I could afford. Second: I spent most of my short time there trying to sate my curiosity about its proprietor. I found myself stealing glances at the Antiquarian from behind piles of books, between shelves, and at one point, over a basket of mismatched socks. There he sat, petrified, in the center of the Emporium, skin of waxy grey over ancient taut sinew, moaning in a voice so dry and brittle it sounded like the snapping of twigs after a drought.
A girl of not more than twelve scurried to and fro to fulfill his numerous requests. Another patron noticed my fascination and told me that the girl-most likely an urchin rescued from the street-was responsible for the needs of the Antiquarian-feeding, washing and the like. So impossibly old is he and so fragile his skin, he can only tolerate the barest whisper of touches from the smallest and most tender of his servants.
"Only in this way may he come close to his lost youth," said the man.
I was surrounded by objects of legend, yet none fascinated me as did the Antiquarian.
From a journal page found in Kirkwall's Darktown, written by an unknown author.
Location: The Mirror of Transformation changing the Inquisitor's appearance
Shop: Emporium's Weapons and Accessories - high-quality equipment
Shop: Emporium's Schematics of Legend - legendary schematics
Shop: Emporium's Schematics - schematics
Shop: Emporium's Crafting Materials - all crafting material (not including exclusive to DLC's)
"Voices on the winds speak of a new power abroad in the world. 'Inquisition,' they whisper-an ancient name restored, a memory rekindled and transformed into a blaze of hope. I hear the whispers and summon the fires of the Inquisition. Here in the depths beneath the City of Chains, countless mysteries hide in shadow in anticipation of the light.
Come. The Black Emporium awaits."
Xenon the Antiquarian must spend his days composing melodramatic invitations to his establishment. I imagine being stuck in a chair for centuries leaves one somewhat lacking for entertainment.
This particular message was hand-delivered by a cloaked figure at twilight, precisely as the sun disappeared beneath the peaks. (My men spied the courier lurking about our outer gates for at least an hour waiting for sunset. A servant under the command of some very specific instructions, I assume.)
That aside, I would encourage a visit to the Black Emporium. The Antiquarian's hoard is legendary; only those he deems worthy ever lay eyes on it. The Champion of Kirkwall received an invitation once and reported (among other things) a strange mirror that could transform even flesh and bone.
Who knows, we may uncover something that aids in the battle against Corypheus.