Wilbur Smith

From jacket of book: When his stepfather's gambling debts leave him a marked man, Francis Courtney feels to South Africa with revenge on his mind. His uncle, Tom Courtney, killed Francis's father. Christopher Courtney gave up a privileged position to become a fierce warrior, but his path led to violence and treachery. When the two Courtney men collide, the sins of the father will change the fate of a younger generation.