The planet Rossak was the fifth planet in the star system HD95424. It was the fourth stop of Zensunni Wanderers during their forced migration times, and where a Awareness spectrum narcotic that released the Other Memories of their Sayyadinas was discovered.
In 10191 AG, the Lady Jessica experienced memories of Rossak when she underwent the spice agony on Arrakis. During the ceremony, Jessica successfully changed the Water of Life poison, thus unlocking her Other memories. It was during the induced trance that she recalled moments, through Other Memory, of the original Zensunni Wanderers on the planet Poritrin, as well as Zensunni women taking awareness spectrum narcotics that unlocked genetic memory for the first time.
The Fremen of Arrakis would recall the raiders pursuing them on Rossak, through courtyards lush with greenery. This recollection would normally take place during a ceremony, along with the raids on Poritrin and Bela Tegeuse. The ceremony would normally involve the Sayyadina, and the words "We will never forgive and we will never forget".
It was a world barely capable of accommodating humans, due to the toxic atmosphere, and volcanic geology that covered all but its equator.
Despite its natural riches, and the protection offered by the planet's equatorial silvery-purple jungles, the Rossak environment still had a devastating effect on its wider human population. Genetic damage was a common problem, and left many newborn humans either still-born or burdened with serious genetic defects.
Rossak was once visited by the Zensunnis, but they eventually were expelled by raiders.
The planet was later most famous for being the home of the Sorceresses of Rossak, a culture of telekinetic women who came into being thanks to the planet's torrid environment. Rossak was also well known for the diverse and pharmaceutically rich flora that grew in its habitable zone. Such was the potential of the native plants of Rossak that groups made a healthy living harvesting and selling them throughout the League of Nobles. The most famous of such entrepreneurs was Aurelius Venport.
Prior to the Jihad, Rossak was assaulted by Cymeks who wanted to exterminate the Sorcesses as a retaliation for the loss of Barbarossa but they were repelled. Rossak again was one of the planets who suffered by the Omnius Scourge.
After the Jihad, Rossak was again a target of the piranha mites, a new assault by besieged Omnius. The danger was soon eradicated, but a new strain of the Scourge, the Rossak Epidemic, made its appearance, mutated in the hazardous rich environment of the planet.