Duke Leto Atreides is the head of House Atreides - a noble, principled leader respected throughout the Imperium for his honour and military prowess. When the Emperor grants him stewardship of Arrakis, Leto knows it is a trap designed by his enemies, the Harkonnens, to destroy his house. He accepts anyway, hoping that the wealth of the spice and an alliance with the Fremen will give him the power to resist. Leto is a tragic figure - a good man navigating an arena where goodness is a vulnerability. His love for Jessica and Paul, his loyalty to his retainers, and his determination to do right by the people of Arrakis make his inevitable fall all the more devastating. Leto's death early in Dune sets the entire saga in motion.

Alia Atreides is Paul's younger sister - born with full ancestral memories after Jessica underwent the Water of Life ceremony while pregnant. This makes Alia an Abomination in the eyes of the Bene Gesserit: a pre-born child who carries the voices and personalities of countless ancestors within her mind from the moment of birth. In Dune, Alia is a terrifying child who kills the Baron Harkonnen. By Dune Messiah and Children of Dune, she has become regent of the Atreides empire, wielding enormous power while fighting a losing internal battle against possession by the Baron's personality within her. Alia's tragic arc - from gifted child to corrupted ruler - is one of Herbert's most compelling explorations of the dangers that come with power beyond human capacity to bear.