He and his shop are involved in this Fighters Guild quest. Norbert is having a lot of break-ins at his store, in the waterfront area of Anvil. He invites the Hero to stay overnight and discover who the thieves are.
Anvil: "Anvil's a port town. That's why you'll see items here you see items here you won't find in the Imperial City. The captains keep an eye out for special items for me."