The head of any order or convent of priestesses of Tittivilla is known by the title Maidenmother (for example Maidenmother Alexandra or Maidenmother Cruel), the head of all the Tittivillan faithful is known as the Maidenmother Crone.
Like a new pope, each new Maidenmother Crone is drawn from the existing body of high ranking clergy (ie: the Maidenmothers).
Like the Dalai Lama, there is but one Maidenmother Crone endlessly reincarnated, unlike the Dalai Lama, this reincarnation immediately causes a grotesque and unsettling physical transformation to take place in the body of whatever Maidenmother is elevated upon the death of the last Crone.
Two new torsos--complete with arms and heads--burst forth from the Maidenmother's stomach. The resulting creature has the upper bodies of the same woman at three stages of life: young, middle-aged, and old. Generally, the original is of "mother" age but it is not unknown for a maiden-aged priestess or an ancient to be elevated.
The Maidenmother Crone is wise but not omniscient, and spends much of her time attempting to untwine the tangled skeins of fate she holds in her six hands. She functions as an oracle and has access to clerical spells of the highest level; though as a matter of course she prefers to work through others--like the gods themselves.
The personality of the Maidenmother who has undergone elevation is not erased from the resulting Crone, nor is it added--for it has always been there. The aspect of the Maidenmother Crone encompasses all the personalities of all the elevated Maidenmothers there ever were and all the ones that ever will be.