Leto II is the second child of Paul to bear that name, the first having been killed as an infant by the Emperor's Sardaukar in Dune.

Paul suddenly finds that he is able to see through the eyes of the infant Leto, allowing him to aim and throw a crysknife that kills Scytale.

Because of the melange ingested by their mother, which causes unusual effects for the Atreides bloodline, the twins are "pre-born", meaning that as fetuses they had been awakened to consciousness and to their genetic memories; they had been born as fully matured human beings in the bodies of infants.

When Bene Gesserit awaken to their "other memories" in the rite of the spice agony, they are adults with fully formed personalities, and can withstand the inner assault of their forebears; the pre-born have no such defense.

Alia is possessed by him, and unconsciously turns against the Atreides empire, plotting to kill Leto and Ghanima and to tear down the Imperium in a bloody civil war.

The knowledge from those uncounted lifetimes which blended themselves within him provided the certainty through which he chose the precise adjustments, staving off the death from an overdose which would engulf him if he relaxed his watchfulness for only a heartbeat.

[2] This layer gives Leto tremendous strength and speed, acting as a living powered exoskeleton and also protection from mature sandworms, who mistake his sandtrout-covered body for a lethal mass of water.

He is almost invulnerable to physical damage; only his face is susceptible to injury, and his single greatest weakness that he shares with the sandworms, an intense vulnerability to water, is a secret.

The old institutions, the Bene Gesserit, the Bene Tleilax, the Spacing Guild, the houses Major and Minor, the Landsraad, the technocrats of Ix, and CHOAM, have all faded from power in the face of Leto's hydraulic despotism: since he has absolute control of the spice on which the whole universe depends, he has the universe in the palm of his hand, and ruthlessly enforces his simplistic order.

This repression has created in humanity a deep and urgent need to explode upon the universe, scattering itself beyond the reach of any single tyrant.

Siona is the second human to carry a gene that makes her invisible to prescience and thus uncontainable by it, the first being the Count Fenring, from the novel Dune.

Thus the tyranny of prescience will end with Siona — humanity can never again be bound by a powerful prescient like Muad'dib or the God Emperor himself.

Inside the first no-chamber, the Ixians grow their replacement for Malky: his niece Hwi Noree, a creature of pure goodness.

Leto planned to wed Hwi in what remains of an old Fremen village near the former Sietch Tabr, but changes his mind at the last instant to use the Museum Fremen's Tuono Village, the place where Moneo had sent Siona and Duncan in an attempt to keep the peace and keep Duncan alive, safe from the God Emperor's wrath.

However, Siona and Duncan, both well aware of the God Emperor's coming and his schemes to breed them, are primed for rebellion, not quiet acceptance.

Although the Atreides (Moneo, Siona) that surround him needed to be shown (by activating their genetically-inherited prescient powers) the absolute horrors that could only be avoided by Leto's apparent tyranny in order for them to support the Golden Path, Hwi is able to understand without having seen any proof the altruism in Leto's actions and the ultimate sacrifice that he had to make... and is able to love him.

The sandworms which once again travel Dune after Leto's death carry, in his words, "a pearl of his awareness locked forever in an endless dream."

More than 1500 years after his death, Leto II is brought back as a ghola on board the no-ship Ithaca in Brian Herbert and Kevin J. Anderson's continuation of the original series, Hunters of Dune (2006).

The current Duncan ghola notes that it had been cruel to bring Leto back without his twin sister, who had been so much of the original's life.

After his memories are returned, he leads the seven sandworms being transported on the Ithaca to wreak havoc in Synchrony, homeworld of the thinking machines.

While it is stated that Leto had foreseen the conflict with Omnius and the thinking machines, the ultimate fate of the Golden Path, or the worms' status on Synchrony, is left open.

[4][5] Laura Fries of Variety wrote, "the mini picks up a great deal of charisma when McAvoy and [Jessica] Brooks [as Ghanima] come aboard as the next generation of the house of Atreides.

"[6] The characters Leto and Ghanima were aged from ten-year-olds to teens for the miniseries, which Emmet Asher-Perrin of Tor.com called "a smart move here, as finding two ten year old kids who had the ability to behave as though they had millennia of ancestral memory bubbling up inside of them was always going to be an impossibility.