Bellonda was a Bene Gesserit mentat Reverend Mother at the time of the attack on Rakis by the Honored Matres and was amongst Mother Superior Darwi Odrade's advisors. Bellonda was also in charge of the Bene Gesserit Archives on the Chapterhouse planet.
An overweight woman who could have easily adjusted her metabolism to control her girth, Bellonda, or Bell, as she was referred to by Odrade, chose to maintain a plump figure (as well as use spectacles) so that she could make a statement of sorts. Bellonda was an acerbic and bitter woman, who always spoke her mind to the Mother Superior. Despite often expressing very strong and different opinions that could have had her banished, Odrade kept Bellonda as close counsel as a form of conscience.
Bellonda is also revealed as a descendant of Reverend Mother Tertius Eileen Anteac.