Miral Alchem was a woman who survived the Bene Tleilax/Corrino take over of Ix from House Vernius, and remained on Ix as an insurgent against the overthrowers.
Miral and C'tair
She did have a Bene Gesserit background and used that to survive in the Xuttuh era of the planet. Miral met up with C'tair Pilru, brother of D'murr Pilru, who was also a resistance fighter, and the two joined forces for a period of time. Eventually, C'tair and Miral came to love one another while fighting the Tleilaxu occupation.
Shortly after the first shipment of explosive wafers from Prince Rhombur Vernius (in exile on Caladan); C'Tair and Miral engineered an attack at four different sites of the Tleilaxu infrastructure on "Xuttuh", in Vernii City. Unfortunately, C'Tair did not see Miral again after this attack.
Axlotl Tank and Death
She was captured by the Tleilaxu and changed into an axlotl tank. Coincidentally, Miral's tank was the one that produced the hyper potent and ultimately failed imitation spice under the Tleilaxu Master Hidar Fen Ajidica's Project Amal. However, the manufactured spice was flawed, and Ajidica went mad, and ended up imploding from the inside out due to the substance.
Miral died when the Bene Gesserit Commando Cristane put an explosive disc in her tank and destroyed a large section of the Axlotl Tank created by Ajidica. Cristane occupied Miral's place until the Second Battle of Ix, when Count Hasimir Fenring destroyed all the evidence of the Amal Project that implicated House Corrino's participation.
Miral Alchem is featured in the novels Dune: House Harkonnen and Dune: House Corrino, in the Prelude to Dune Trilogy.