Mistress of Shadows
Shield of The Children
In practice, Mistress of Shadows is mostly just a variation of the title Mother of Shadows and as such, given in the same circumstances. However, as the children view motherhood as an important milestone and measurement of one's maturity and character, they reserve word "mother" only for those who have given birth to children. As such, childless Mother of Shadows is referred Mistress of Shadows.
If the title would fall in the hands of a male relative, the male version of the title would be Master of Shadows.
Mantle of Motherhood
As a remnant from times, The Children have kept elements of the female supremacy in their culture. Prominency and severity of the effects of this belief vary through times and from person to person, but females, and most importantly, mothers carry the highest respects of their society. For The Children, one of the biggest reasons for this reverence is the ability of the females to give birth to children and bring life.
As such, the word "Mother" has a connotation of the most prestigious title, used in most formal cases and strictly from those who have reared children. Matron of a great house can be called Mother of the house, but if the matron is currently childless, word Mistress is used instead.
Only significant difference between Mistress and Mother of Shadows is that Mistress of Shadows is seen as incomplete and juvenile version of the Mother. As such, their words more likely gets questioned, and they spend more time observing the other matrons and learning from them. Great Matron Council will continue to respect the Mistress of Shadows and her word, but often take more weight off from them until there is a child to call them mother.
As such, maybe the most crucial duty of Mistress of Shadows is to produce a child, hopefully, a daughter to be their heir.