Gonnar Oath-Giver is a Nord Stormcloak captain.
Background[]
He is the Stormcloak commander of The Rift and can be found in Mistveil Keep in Riften, unless the Dragonborn takes Riften for the Empire during the Civil War, after which he can be found commanding the Rift Stormcloak Camp near the Rift Watchtower.
He is an essential character, so he cannot be killed.