Gurney Halleck

Halleck is Paul's weapons teacher, as well as a skilled musician. He is one of Leto's chief officers, and serves alongside Duncan Idaho as a Swordmaster of House Atreides. According to Dune, Gurney was trained by "the best fighters in the universe", and alongside Idaho and Thufir Hawat gave Leto a war council almost unparalleled in the Imperium. He manages to survive the fall of House Atreides on Arrakis with 73 men. In the years after the attack, he falls in with the melange smugglers, eventually becoming a powerful figure. His smugglers fall for a Fremen trap—a fake hoard of spice—and are almost killed before Paul, now the Fremen leader "Muad'Dib", recognizes him. Halleck later becomes Jessica's loyal chief officer after nearly killing her, mistakenly believing she betrayed Duke Leto.

In Children of Dune, Gurney returns to Arrakis with Jessica from Caladan. He coordinates a purging of dissidents along with Fremen leader Stilgar, an operation that he kept secret. He goes to the sietch Jacurutu under what he believes are Jessica's orders to test that Paul's son Leto II has not fallen to Abomination. When the Fremen Namri reveals that the testing was ordered by Alia, he kills the man and escapes, sending a message to Duncan to set off the course of events that will force Stilgar to act. He takes temporary shelter with a new batch of smugglers before stealing an ornithopter. With it, he escapes to a rebel sietch, where Leto II and The Preacher arrive. Leto II takes him to Shuloch. After Leto II returns to Arrakeen and takes the throne, Gurney is assigned to Sietch Tabr as part of Stilgar's council.

Gurney's character is further explored in the Prelude to Dune prequels (1999–2001) written by Brian Herbert, Frank Herbert's son, and Kevin J. Anderson.

According to the prequels, Gurney Halleck was born on Giedi Prime, the homeworld of House Harkonnen. After an incident with the local militia and the murder of his sister, he escaped Giedi Prime and aligned himself with the rogue House Vernius. Eventually, after a string of conflicts and the death of Earl Dominic Vernius, Gurney Halleck arrived at the Atreides homeworld of Caladan seeking the exiled Prince Rhombur Vernius. After helping reclaim the planet Ix for House Vernius, Halleck served House Atreides, eventually becoming Paul Atreides' weapons teacher.

In Chapterhouse: Dune (1985) it is revealed that the Tleilaxu Master Scytale possesses a hidden nullentropy capsule containing cells carefully and secretly collected by the Tleilaxu for millennia, including the cells of Paul Atreides, Duke Leto, Jessica, and Gurney. A ghola of Gurney is "conceived" in Sandworms of Dune (2007), a sequel to the original Frank Herbert series written by Brian Herbert and Kevin J. Anderson, but is killed during gestation in an act of sabotage.