She is the leader of her kind, referring to them as her brood. However, she was captured by the Beastlords of Mardin, and was used by them to gain control over the deathclaws. She was liberated by the Warrior of the Brotherhood of Steel. Thankful, she permitted some of her kind to join the Brotherhood, and even joined it herself.
Mother appears only in Fallout Tactics.
Her appearance is different in the various settings where she is encountered:
In Mardin she appears with pure white fur and is labelled as "Matriarch".
In Bunker Gamma she appears with pale gray fur and is labelled as "Matriarch" as she runs around the garage area.
When recruited into the party she appears with dark gray fur and is labelled as "Mother". It is done, probably, to distinguish two separately-programmed models that made up this character: a recruit and quest-important character.