In the service of the ruthless Baron Vladimir Harkonnen, De Vries is a Mentat—a human specially trained to perform mental functions rivaling computers, which are forbidden universe-wide. In addition, De Vries has been "twisted" into an amoralsadist by the Tleilaxu. De Vries is so loyal to Harkonnen that he continues to serve the Baron with great enthusiasm even though his Mentat abilities and great intelligence confirm his suspicions that his master plans to eventually kill him. As he says in Dune: De Vries is described in the novelDune as being addicted to the drug melange, which has colored both the sclera and irises of his eyes a characteristic deep blue. He also has the characteristic ruby red lips of sapho drinkers.
Appearances
''Dune''
In Dune, it is established that De Vries had pioneered a type of toxin called "residual poison" which remains in the body for years and requires an antidote to be administered regularly. One such fatal poison is secretly administered by the Harkonnens to Thufir Hawat, the Mentat of House Atreides, in order to guarantee Hawat's allegiance to the Harkonnens, who alone possess the antidote. De Vries is the architect of the plan to destroy House Atreides, longtime enemy of the Harkonnens, while restoring the Baron's stewardship over the planet Arrakis. Dr. Wellington Yueh, personal physician to House Atreides, has undergone Suk conditioning, which renders him incapable of inflicting harm on his patients. De Vries breaks this conditioning through torture and psychological manipulation, and Yueh eventually betrays House Atreides. De Vries originally plans to claim Lady Jessica, the concubine of Duke Leto Atreides, as his slave, but he decides to become governor of Arrakis instead. However, Yueh has given the captured Leto a false tooth filled with poison gas. When Leto crushes the tooth, the intended victim Baron Harkonnen escapes, but Leto and De Vries die.
''Prelude to Dune''
In , Piter De Vries discovers the Harkonnen heritage of Lady Jessica and her newborn son Paul, and attempts to kidnap and ransom the infant. The plot is thwarted and the secret preserved—the Reverend MotherGaius Helen Mohiam kills the Mentat and arranges for his corpse to be shipped home to Giedi Prime. An enraged Baron is left with no choice but to order a duplicate from the Bene Tleilax: the Mentat De Vries featured in Herbert's original novel Dune.
De Vries is portrayed by Brad Dourif in David Lynch's 1984 film Dune, and by Jan Unger in the 2000 Dune miniseries. The character will be played by David Dastmalchian in the 2020 Denis Villeneuve film Dune.