Who is Reverend Mother Lucilla from Chapterhouse: Dune and what is their importance?

Reverend Mother Lucilla is the Vice-Chancellor of the Bene Gesserit's premier school on Lampadas, Lucilla is ordered to flee at the first sign of trouble, but makes it only to Gammu, where she is hidden by a Rabbi of "Secret Israel." Lucilla shares her memories with the wild Reverend Mother Rebecca and is turned over to the Honored Matres as a decoy to save the other Israelites hidden with Rebecca. On Junction, Lucilla is caged and denied food - so she will be lean meat for the Futar. Lucilla endures several days worth of interrogation and conversation with Grand Honored Matre Dama before angering Dama to the point that Dama murders Lucilla ("the witch"). The hordes of memories from Lampadas encourage Lucilla to practice restraint up to the end, and she has Dama ready to welcome her into the Honored Matres before she makes a slip of the tongue.