Parmentier is a former Synchronized World, recolonized by the League of Nobles during the Butlerian Jihad. Quentin Butler's forces liberated the planet in 150 BG and appointed his eldest son Rikov Butler as temporary governor.
After Parmentier is ravaged by the Demon Scourge (Omnius Scourge), a catastrophic virus genetically engineered and unleashed by the thinking machines to destroy humanity. During that time Rikov Butler was fulfilling the role of Governor. Rikov and his wife were killed by the Scourge, but their daughter, Rayna Butler survived and went on to found the fanatic anti-technology movement known as Cult of Serena.
Soon after, Abulurd Harkonnen was sternly ordered by his father to return to Parmentier and investigate whether the virus has run its complete course and subsided. Vorian Atreides accompanied him and authorized an immediate field promotion of him to Tercero. After performing a proper burial to the decaying bodies of his brother and his wife, he met his niece, Rayna and brought her to Salusa Secundus.
Sources: Dune: The Battle of Corrin?
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