Twisted Mentat

The original series

The Tleilaxu control a number of planets but are originally connected with Tleilax, the sole planet of the star Thalim. Herbert's 1965 novel Dune notes that the Tleilaxu are the source of twisted Mentats. Baron Harkonnen states his intent to "send at once to Tleilax for a new Mentat" after Piter De Vries is killed. The Tleilaxu themselves step into the foreground in Dune Messiah as their Face Dancer Scytale enters into a conspiracy with the Bene Gesserit, Spacing Guild, and House Corrino to topple the rule of Paul Atreides. To this end, the Tleilaxu resurrect Paul's dead friend Duncan Idaho as the ghola Hayt, trained as a Mentat. Hayt's function is to unwittingly destroy Paul psychologically and, failing that, kill Paul when triggered by an implanted command. The emotional stress of this assassination attempt unlocks Duncan's memories in Hayt, which Scytale uses to illustrate that the Tleilaxu can provide Paul with a fully realized ghola of his deceased concubineChani, in exchange for his abdication. Paul refuses and kills Scytale. Duncan further ponders the Tleilaxu legacy of his creation in Children of Dune (1976).