My favorite is Arutha, and while there are several reasons, the big one for me is that of all the main characters portrayed as eventually becoming fathers, Arutha is the only one of the bunch that is portrayed as showing a stated involvement in the lives of his children. Pug was a rather neglectful parent, and Tomas is shown (or even mentioned) interacting with his son on one occasion. We're not told much of James, but I gathered from listening to his son that his relationship with The Hand was somewhat distant.
Arutha was a good and involved father AND surrogate big brother to Jimmy (a relationship which I enjoyed a lot). So he wins.