The Star King (The Demon Princes 1)

Blurb

Star King is a science fiction novel by American writer Jack Vance, the first in his Demon Princes series. It tells the story of a young man, Kirth Gersen, who sets out to track down and revenge himself upon the first of the Demon Princes, the five arch-criminals who massacred or enslaved nearly all the inhabitants of his colony world when he was a child.
Star King was originally serialized in the December 1963 and February 1964 editions of Galaxy magazine, as The Star King. The antagonist of the book was originally known as Grendel the Monster, and was subsequently renamed Attel Malagate for the novel version. The magazine version featured striking cover and interior illustrations by Ed Emshwiller.
Though Vance won the 1963 short-story Hugo award for "The Dragon Masters", Star King did not win the award as is half-suggested by early cover designs.