Avulstein Gray-Mane

Avulstein Gray-Mane is a character in The Elder Scrolls V: Skyrim. He is an old warrior looking for his missing brother Thorald Gray-Mane who disappeared after helping the Stormcloaks. If the player chooses, they can join him in a quest, Missing in Action to rescue his brother from the Northwatch Keep where he is kept by Battle-Born.

He will offer to help you rescue Thorald Gray-Mane once you bring him evidence of his capturing. You have the option then to have him come along, or find a peaceful way of rescuing Thorald.