Arnbjorn was the husband of Astrid and the enemy of Fün Tits. He was one of Fün's suspects, along with Babette, of setting her up after the emperor's assassination attempt. His hobbies included sitting around and twiddling his dick while Fün was out in battle.
Since Arnbjorn liked to belittle Fün by calling her food names, she, in turn, came up with many nicknames for Arbjorn. Some of her nicknames for him include, Beef Slippers, Beef Prostitute, Gut Nuts, Bulorganorg, and the drummer from Abba.
Arnbjorn can be seen in the background while Fün Tits was talking to Nazir. Soon after, Fün Tits finds him and mistakes him for the guitarist from Abba. He then tells her that he has a wife. Emre, the voice in her head, breaks the news to Fün that Astrid is a married woman. This is when her one sided feud start with Arnbjorn.
Fün and Emre come up with a plan to seduce Arnbjorn (with her Sex Armor) to break up marriage with Astrid.
Arnbjorn finally dies in the raid on the Sanctuary when he was killed by Penitus Oculatus Agents while in werewolf form. Although Fün thinks Astrid is now hers, she is worried Astrid might also be in trouble.
In Season 6, Fün references Arnbjorn upon arriving at the Brotherhood Sanctuary. Oddly, a former Dark Brotherhood member named Averna tells Fün why she left the Dark Brotherhood. According to her, she and Astrid were lovers until Astrid married Arnbjorn. This made her jealous and prompted her to leave.
- "My beautiful wife has told me all about you."
- "I love Astrid."