God Emperor of Dune, places us in a universe vastly different from that of Children of Dune. Leto II still lives, having ruled the Empire for more than three thousand five hundred years. He owes his lifespan to a decision Leto makes in Herbert's previous novel to merge his human body with sandtrout. Leto continues to evolve into a worm, his only remaining human features being his face, tucked in a cowl of wormflesh, and his hands. Leto's legs are nothing more than useless flippers. Leto moves about on a giant mechanical cart equipped with both wheels and suspensors resembling a tank chassis. To the Imperium and to the reader of the book, Leto appears to have changed even more dramatically in ethics than he has in appearance. The third book in the series, Children of Dune, saw Leto II as a hero that would lead humanity along a shining golden path. Now, millennia later, Leto's rule appears to be nothing more than the most depraved despotism humanity has ever witnessed. The worm, as he's called, however, appears confident in the direction of his course despite everyone's inability to see how this could possibly be part of the Golden Path or good for humanity in any way.
The book opens with a deadly chase: a band of rebel humans pursued by a pack of deadly, genetically modified wolves known as D-wolves. One by one, the wolves pick off the rebels who have successfully stolen some documents from Leto's keep. When we join the chase, only three rebels remain on their feet. The wolves immediately take down one of the rebels, compelling the penultimate runner, who is hampered by an injury, to make a brave stand to try and give the last runner a few more precious minutes. The last runner, a woman on her final reserves, makes the safety of the opposite bank of the Idaho River. From this safety, Siona, looking across at the baying wolves, curses the Emperor of Arrakis, a curse made all the more meaningful, because we learn that she, like Leto, is of the Atreides family line.
Purportedly to ease the loneliness of the centuries, Leto commissions the Tleilaxu to produce one Duncan Idaho ghola at a time. Each Duncan serves Leto as a personal companion and as the leader of his female Fish Speaker army. During a heated discussion with a Duncan ghola, Leto, warned by the Spacing Guild, is aware that Duncan is armed with a lasgun purchased from an Ixian, and intends to assassinate Leto. Leto is not particularly shocked. The reader later discovers that most of the Duncan Idaho gholas eventually turn against Leto before being killed. Having been the loyal swordmaster to House Atreides, as well as Paul's teacher and close friend, Duncan struggles with internal conflict over his allegiance to the Atreides family in opposition with his moral deference to the people he sees as being oppressed by the God Emperor, all clouded by the uncertainty of feeling millennia out of his time. Moneo (Leto's canny majordomo; the name is a Latin verb whose root comes from mens or "mind" in the sense of reminding or admonishing[2]), who refers to the Duncan ghola during an altercation as being an "older model," considers Duncan's social mores and virtues to be outdated and at extreme odds with Leto's Golden Path. Duncan demonstrates his naïveté in some areas, during a discussion with Leto concerning the failures of aristocratic and ruling classes.
