metamorphose

In fact, perhaps this is the pure and perfect incest: the brother realising that the sister’s virginity must be destroyed in order to have existed at all, taking that virginity in the person of the brother-in-law, the man whom he would be if he could become, metamorphose into, the lover, the husband; by whom he would be despoiled, choose for despoiler, if the could become, metamorphose into the sister, the mistress, the bride.