In Heretics of Dune (1984), Schwangyu is in charge of the Duncan Idaho ghola project on Gammu. As the leader of a faction of the Sisterhood who believe that such gholas are a danger to the order and its goals, she has been subtly encouraging the ghola's failure. By the time Lucilla arrives to teach Idaho and bind his loyalty to the Sisterhood with sexual imprinting, he has already been tarnished by Schwangyu and nurses hate for the Bene Gesserit, hoping to escape their control of his life. Despite Schwangyu's efforts to seduce Lucilla to her side, Idaho blossoms under the training of Lucilla (and Miles Teg), and Schwangyu begins to realize that she has much underestimated Lucilla.
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