Duncan Idaho is House Atreides’ Swordmaster, and he operates as both a bodyguard and a warrior for the Atreides family. Along with Thufir Hawat and Gurney Halleck, he is one of the Duke Leto Atreides’ most valued and trusted men. Idaho is entrusted with becoming an ambassador to the Fremen upon the Atreides’ arrival on Arrakis, in the hopes that he might find avenues of communication and allies within the tribes. In the process, both the Fremen and Idaho take a liking to each other, and Idaho is allowed to swear dual allegiance to both House Atreides and the Fremen.

Staunch loyalty and morality are Idaho’s strongest traits. As an accomplished warrior, he lives to serve worthy people and worthy causes, putting himself at great personal risk for both the benefit of House Atreides and the Fremen. It’s no wonder that he made a good impression on Stilgar, who also values loyalty, respect, and living in service to a greater purpose. In allying himself with the Fremen, Idaho opens vital channels of communication between House Atreides and the native tribes, which aids in Jessica and Paul’s survival after their escape from the Harkonnen attack. Idaho himself dies while attempting to save Jessica and Paul, further highlighting the level of personal sacrifices that must be made in order to ensure the survival of a House.