Leto is the God Emperor of the known universe, having ruled for over 3,500 years. He has merged his body with larval sandtrout, becoming a massive human-sandworm hybrid with only his human face and hands remaining. He possesses universal prescience and the memories of all his ancestors, using these powers to enforce a tyrannical tranquility across his empire. His ultimate goal is to guide humanity along a breeding program and survival plan he calls the Golden Path.

Duncan is an artificially created human grown from the cells of the original Atreides swordmaster. As the latest in a long line of identical replicants serving Leto, he struggles with his identity and his dislocation in a strange future. He holds tight to the original honor and principles of the Atreides family, which frequently puts him at odds with Leto's brutal methods and religious cult.

Moneo is Leto's majordomo, a 118-year-old direct descendant of the Atreides line who refuses life-extending spice. Once a rebel, he is now completely subservient to Leto after undergoing a terrifying test that revealed the necessity of the Golden Path. He manages the daily bureaucracy of the empire while constantly fearing the unpredictable emergence of Leto's violent sandworm persona.

Siona is a young, fierce rebel against Leto's regime and the culmination of his millennia-long breeding program. She possesses a unique genetic trait that makes her invisible to prescient visions. Driven by anger over the oppressive nature of Leto's rule and the deaths of her rebel companions, she dedicates herself to finding the God Emperor's weaknesses.

Hwi is the new Ixian ambassador, bred and conditioned specifically to appeal to Leto. Born in a chamber shielded from prescience, she possesses a gentle, pure, and highly empathetic nature. She intuitively understands the massive personal sacrifice Leto has made for humanity, awakening his repressed human emotions and desires.

Nayla is a member of the Fish Speakers, Leto's all-female army. She operates as a double agent, maintaining Siona's trust as a confidante while using secret implanted technology to report directly to the God Emperor. Her religious devotion to Leto is absolute, causing her to accept even his most contradictory commands without question.

Malky is a former Ixian ambassador known for his crass, provocative nature. He once served as an intellectual sparring partner for Leto, actively encouraging the God Emperor to embrace technological advancement rather than suppress it. The Ixians use his genetic material to engineer Hwi Noree as his exact psychological opposite.

Hadi Benotto is an archaeologist living in the far future. She works to translate and preserve the audio recordings and written journals of the God Emperor, arguing against religious authorities who wish to censor the historical documents.

Anteac is a Bene Gesserit Reverend Mother tasked with securing her sisterhood's access to melange. Pragmatic and politically calculating, she maneuvers through Leto's dangerous court by balancing appeasement with subtle plots to test his vulnerabilities.

Luyseyal is a Bene Gesserit Reverend Mother who assists in managing the sisterhood's fragile relationship with Leto. She works alongside Anteac to secure their spice supply while investigating rumors of new Ixian technology.

Sister Chenoeh is a Bene Gesserit operative from earlier in Leto's reign. Her documented interactions with the God Emperor provide historical context for his long-term plans, recording his early admissions about his spiritual alliances and inner torments.

Paul Atreides, known as Muad'Dib, is Leto's father and the former Emperor of the known universe. Though deceased, his presence looms heavily over the narrative. Leto often accesses his father's memories, contrasting Paul's refusal to enact the Golden Path with his own willingness to become a monster for humanity's sake.

Ghanima is Leto's twin sister who lived thousands of years ago. Like Leto, she was born with ancestral memories. Leto retains deep sentimental attachments to her memory, keeping physical tokens of her existence hidden within his Citadel as a reminder of his lost humanity.

Iyo is the Ixian ambassador prior to Hwi Noree. He is banished by Leto for supplying weapons to rebels but remains involved in underground conspiracies, funneling information about Ixian navigation projects to Siona's resistance cell.

Topri is Siona's assistant in her rebellion against Leto. He attempts to prove his dedication to Fremen traditions by purchasing a black-market replica of a crysknife, though Siona eventually uncovers that he is secretly working as an informant.

Duro is the Tleilaxu ambassador to Leto's court. Following a failed Tleilaxu assassination attempt on the God Emperor, Leto orders Duro to be publicly flogged based on fabricated charges, using him as a pawn to teach a lesson about personal responsibility and to incite controlled rebellions.

Garun is the leader of the Museum Fremen delegation in Tuono Village. He performs outdated and commodified versions of ancient desert rituals for tourists, lacking the true survival skills of his ancestors, which earns him the initial scorn of Duncan Idaho.