The Traveling Merchant
Reed Bellows is a merchant on the road outside Meridian, approximately at 6380, 5157, just north of the base of the path up to the Meridian gates. Killing him unlocks the Merchant of Death achievement and title.
After killing him everything disappears: the yellow NPCs, the construct, and the wagon.
You do have the choice to kill Reed or the bandits, it is suggested to get a group of people together who want to kill this NPC, as his respawn timer is known to be long.
The Merchant Inside Meridian
Once Reed gets to Meridian he has a shop, he sells books right next to Enrinke Shinuas the Artifact Collector in the Epoch Plaza. He is never there for very long, so buy from him quickly.