Warning: the following contains major SPOILERS for Dune and future installments in the franchise.
Dune 2021’s protagonist is clearly Paul Atreides, but Jason Momoa’s Duncan Idaho has an even larger role to play as the saga continues. Denis Villeneuve’s 2021 adaption of Dune is based on just the first half of Frank Herbert’s seminal 1965 sci-fi novel, with Dune: Part Two set to focus on the second half of the book when it releases in 2023. Villeneuve has plans to turn his new reboot into a trilogy, with the third movie being based on Dune: Messiah, the second book in Herbert's acclaimed series.
In Dune: Messiah, Duncan returns as a ghola—or clone created by the Bene Tleilax—serving Paul (Timothée Chalamet), who at that point in the story has become the Emperor. This could setup Jason Momoa for a return in the potential third Dune movie, as Duncan was killed off in the first installment while protecting Paul and Lady Jessica from Sardaukar soldiers. Should Villeneuve's planned trilogy continue even further, its source material provides plenty of opportunities for Momoa to keep reprising his role.
Dune’s Duncan Idaho is the only main character who appears in all six original Frank Herbert books. In Dune: Messiah, Duncan Idaho is reborn as a ghola named Hayt, trained as both a mentat and a Zensunni philosopher programmed to kill Paul. Hayt foils the Bene Tleilax assassination plot when his inherent loyalty to Paul contradicts his programming, leading to the character recovering all memories of Duncan’s life. Paul’s son, Emperor Leto II, along with the Bene Tleilax and the Bene Gesserit, create thousands of Duncan Idaho gholas throughout Dune’s long timeline, and many not only recover Duncan’s original memories, but also the memories of previous gholas. The final Duncan ghola eventually reaches a level of prescience and devotion to the Golden Path that even Paul himself never achieves.
Out of the thousands of Duncan Idaho gholas that Leto II creates throughout his 3500-year reign, only 19 die of natural causes, while the others inevitably rebel against Leto II’s tyrannical rule. After Leto II’s death, the Bene Tleilax and the Bene Gesserit use those gholas to plot against each other. This eventually leads to a "Duncan" that remembers all the memories of its previous incarnations, most of which are acts of loyalty and heroism as the character's core virtues and personality never change throughout the Dune saga.
While the story of Dune 2 will more than likely cover the ascension of Emperor Paul Atreides, the third movie could potentially set up the beginning of Duncan Idaho’s karmic journey. If Dune: Messiah is adapted to film, Villeneuve’s reboot could potentially reveal the true main character of the Dune saga. This isn’t to say that Paul isn’t a key character, as both Paul and Leto II serve as warnings against following even the most promising leaders and messiahs, which Frank Herbert himself has explained to be the whole point of the Dune series. While Paul and Leto Atreides represent the well-meaning but ill-fated messiahs of history, Duncan Idaho represents the rest of humankind, with all the wisdom and pain that comes with age, struggle, and experience.
