Mistress Doll is a member of Falstaff's gang.
Doll is a gifted gymnast and martial artist, able to quickly ambush and incapacitate foes as powerful as Fang.
Real World Background
Mistress Doll is named after Doll Tearsheet, a character in Shakespeare's Henry IV Part Two. A prostitute and Falstaff's mistress, she appears in Act Two, Scene Four, where she and Falstaff have dinner at the Boar's Head Tavern. At the end of the play, Mistresses Doll and Quickly are arrested by the police in connection with a murder committed in the tavern; Doll tries to make things easier for herself by feigning pregnancy (apparently through stuffing a cushion under her clothes); the ploy fools nobody. In Henry V, she is described as in the hospital, suffering from syphilis.