The Return of the Honored Matres referred to the arrival of the Honored Matres from uncharted space into the Known Universe.
During The ScatteringEdit
The group's emergence saw them come into direct contact with the Bene Gesserit, one of the groups, including the Fish Speakers, and recovered women from Tleilaxu axlotl tankss, from whom they had evolved in the turmoil of the Scattering. They came with formidable military forces which they had built up in the previous thousand years, and overpowered numerous worlds weakened by the erosion of many established political players. One such world was the planet Junction, which the Honored Matres captured from the Guild.
After subjugating both the Spacing Guild and the Bene Tleilax, the Honored Matres embarked on an aggressive campaign to destroy, and before doing so, learn the knowledge of the Bene Gesserit. However, their plans of destruction failed, and the two groups effectively merged under the leadership of Murbella, as Mother Commander of the New Sisterhood. This outcome effectively marked the end of the Honored Matres' return to the known universe.
Fleeing from the Thinking MachinesEdit
It was finally revealed that the Enemy the Honored Matres were in fleeing from was the reborn Thinking Machine empire, led by none other than human-kind's age old enemies Omnius and Erasmus. Murbella, through an enhanced dosage of the spice melange, accessed repressed parts of her Other Memory. She discovered that a Matre leader, Lenise, and her minions had stumbled across an outpost world of the Machine Empire, attacked it, deicmated it, and stolen some super-weapon Obliterators.
Lenise and her group, as well as the whole Matres Empire, were quickly counterattacked, and found themselves outnumbered and dying under the spreading of the newly launched and re-crafted Omnius Scourge. Abandoning their planets they had colonized during the Scattering, including Rikka's Planet, the Matres fled and attacked towards the Old Empire, leading the machines to the remaining bulk of mankind.
The knowledge that the returning Matres craved was the Gesserit women's ability to control their own body chemistry. It was believed by Matres leaders that this ability would effectively combat the Scourge.
The Return of the Matres was the major factor for the beginning of Kralizec, which had been foretold eons before as the great change that would forever alter the course of the Known Universe.