Kupiec Wędrowiec (The Mysterious Merchant)

(Pronounced: cu-petz, ven-dro-vetz).  Kupiec is a mysterious humanoid entity who seems to rather enjoy buying and selling things.  He covers his identity by wearing a dark cloak with the hood up and a purple cloth mask wrapped around his face.  You can only see a small portion of his pale skin and his eyes which are an abnormal bright yellow.
He has revealed very little about himself.  He has mentioned some type of connection to the Goddess of Trade.  He had the ability to teleport between different planes of existence at will and can also move items in this way.
Seemingly by whatever connection he has to the Goddess of Trade, he is always fair and upfront in his deals.  All terms are made clear and are final.  He will never go back on his word, or swindle anyone with a raw deal.
He was first encountered by the party at the Temple of Trials. There will shop bells that the party could ring in various rooms though out the temple to essentially summon him in order to trade with him.  He indicated that he had a deal with the group who built the temple to provide this service until the day that someone actually managed to complete its trials.
He can appear basically whenever and wherever he wants to.  He also indicated that there are other Merchants like him out there.
The last time he was encountered, he was offering the following magic items: +1 Arrows, or +1 Bolts at 50 gold each Potions of Healing at 50 gold each Potions of Greater Healing at 150 gold each Belt of Hill Giant Strength at 500 gold Bracers of Archery at 125 gold Elven Chain at 600 gold Rod of the Pact Keeper +1 at 200 gold Scimitar of Speed at 5,000 gold Wand of Magic Missiles at 220 gold Periapt of Wound Closure at 450 gold Ramen Noodles at 1 copper