|Location||Cellar of Jarl Olfwenn's Hall, Karthwatch|
Jarl Olfwenn is the ruler of the hold of Karthald and can be found in the town of Karthwatch. Svana will want an audience with her so she can gain the Jarl's support in convincing High King Svargrim to take action.
However, when you arrive you will find the town have been hit by a harrowstorm and most of the citizens dead. While looking for the Jarl, you will find her wizard Magister Fridelja who will tell you that she sent the Jarl into the cellar to hide. When you and Svana check the cellar, you will find Jarl Olfwenn has degenerated into a Harrowfiend and is crouched in the corner and grabbing at her crown. You will need to retrieve the crown and put Olfwenn out of her misery.