Kveldulfr is a smith in Skjern located close to the longhouse. In the first act he can repair armour and weapons. In the second chapter, depending on the chosen upgrade tree for the smithy, he can also make weapons or armour when thegn of Skjern gives him a commission.
Cleaning house and the Northmen's Raid
If you spared the Erlingrsons at the end of The Feast, he, along with Sigridr joins the party temporary to pass judgement on Erlingr and assist you in battle in case that is unavoidable.
During the The Northmen's Raid, he will join you party temporary to fend off the invaders from the south.
When he joins your party during those battles, he has the following stats. Despite being a smith, he has no skill points invested in artisan, armoursmithing, crafting or repairing. And he has the walk your shot passive ability, while he doesn't have 6 perception.