Ethereal Soul-Trader

Ethereal Soul-Trader is an ethereal companion who sells wares using a unique currency to players.

Source
They can be summoned using the, which can only be received through World of Warcraft TCG (trading card game). The currency is obtained from getting the killing blow on something that counts towards honor or experience for the player.

Pet Journal
Ethereal soul-traders will travel with those who can free the essences they need from unruly hosts.

Details

 * TCG Expansion: Hunt for Illidan
 * Card: Ethereal Plunderer

Quotes
When summoned:
 * say

Occasionally when siphoning Essence:
 * say
 * say

How may this one help you, ?
 * Gossip


 * My business partner slays things; I drain a portion of their essence... a pittance, really; the slightest of slivers. It won't be missed.
 * Still, to fulfil [sic] my portion of the contract, I pay in Ethereal Credits.
 * One may redeem these credits for items I sell at any time. I'm bound to have something that will interest you...