(Count) Hasimir Fenring is a character from Dune. I always thought he was a great character despite that he didn't have an overwhelming role in the plot. He was basicly an agent of the emperor, not in the least place a talented assassin. Despite the fact that he was a loyal friend to the emperor, he eventually refused to carry out an order to kill somebody (either because of affection, honor or both- it isn't made very clear) wich cost the emperor dearly.

The prequels written by KJA Anderson and Brian Herbert put him more in the spotlight, but made him look like a two dimensional sociopath