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

Exiled to "special perdition" years ago for an "unforgivable infraction" (an illicit love affair probably), Dortujla shows up at Chapterhouse with word that a delegation of Futars and Handlers wants to ally with the Bene Gesserit against the dreaded Honored Matres. This woman, who has not let her exile dull her, impresses Reverend Mother Superior Darwi Odrade. While she would prefer to keep Dortujla near her on Chapterhouse, Odrade bows to her judgment that she is needed on Buzzell, where she intends to be bait to draw the Honored Matres into negotiations. Dortujla is tortured by the Honored Matres but returns with word that a meeting is arranged to accept the Sisterhood's surrender. Dortujla accompanies Odrade on the suicide mission and dies at the outbreak of battle.