She was offered by Reverend Mother Croesia offered to Vladimir Harkonnen as a concubine; although he preferred young boys, he proceeded without questioning her motives. There are several theories on why.
The affair was stormy and brief during which Tanidia became pregnant. She fled from Harko under threats and vanished in the eighth month of her pregnancy.
In Croesia's Memoirs there a short exchange from Tanidia's report to her superior shedding light on what occurred with Harkonnen:
- CROESIA: You are aware how much this has cost us. There must be no question as to your child's parentage.
- TANIDIA: There is none, though subliminal arousal techniques were necessary to overcome his impotence.
- CROESIA: Such techniques weren't necessary with his boys.
- TANIDIA: As our psychological profile indicated, his misogyny is deeply rooted but ambivalent. Inverted idealization of the anima reflects on his own childhood. Thus the love for the young boys — himself in his own mind. The murder of Muertana was a release, but there is strong reason to believe that before he murdered her they—
- CROESIA: Now he channels it through repression and hatred, reverting to himself unconsciously. Good. It is a lever, should we/ever need it. You have done well, my dear. You will bear a daughter, of course.
Many scholars rejected Leto's identification of Nerus as Jessica's mother on the grounds that it was made before Leto had begun any investigation of his ancestral memories, before he became emperor and ascended the Lion Throne, and before he had access to the Bene Gesserit breeding records.
Through later sources particularly those of the Lady Ghanima, Duncan Idaho-13015 and the Journals of Leto II, it is seen that Jessica's mother was the Bene Gesserit Reverend Mother Gaius Helen Mohiam, who used the name Tanidia Nerus, and that's why any written record of her was merely part of an attempt to keep Mohiam's identity secret.
- HARKONNEN, VLADIMIR
- MOHIAM, REVEREND MOTHER GAIUS HELEN
- NERUS, TANIDIA