Ylva

In my opinion, Ylfa is the best supporting character in the series. She is kickass, strong, and doesn't swoon over her (many) admirers.

Personality
As I previously mentioned, Ylfa is the best, most kickbutt person in the series. Being a Viking's daughter, she deals with her neighbours and friends changing quite often. A Viking's life is not very stable, even if you're a girl and don't go to fight.

Role in the Series
When Thors dies and Thorfinn doesn't come home after escaping with his father on a warship, Ylfa becomes the main supporter of the family, especially since her mother is of very frail nature. In fact, Ylfa is seen as quite a rebel and maniac/crazy girl by the village. This is probably because she has to fish, whale, and all the women's jobs too. In fact, soon after the loss of two family members, she overcompensates by working. In the end, Helga has to teach her self-control.