Who is Murbella from Heretics of Dune and what is their importance?

Murbella is a young Honored Matre postulant on Gammu, Murbella has observant green eyes and wears a a dragon robe over her willowy body. She insults Burzmali and would have killed him as male scum, had the Reverend Mother Lucilla not dropped her with a standard Bene Gesserit move. Gasping, Murbella addresses Lucilla as "Great Honored Matre," and explains that she is newly robed and thankful for the lesson. She had earlier knocked out the fugitive Duncan Idaho and sexually "marked" him.