Fanny Fulbright speaks with a thick Scottish accent and has a loud voice, especially when yelling, which she does often. She is rude, ill-tempered and mean, but is strongly loyal to the Kids Next Door. In fact 86 can mean to be negative whether the writers intended her to be Numbuh 86 for that very reason is unknown. As mentioned above, she has a strong distaste in boys, most notably shown during her first appearance, Operation: F.U.G.I.T.I.V.E., where she essentially takes Numbuh 1, Numbuh 2 and Numbuh 4 out of a mission simply for being boys and readily listens to Numbuh 5 and Numbuh 3.
She does seem to have a soft side, however. In Operation: M.A.U.R.I.C.E., she cries (along with everyone else) when beloved male operative Maurice is decommissioned. In Operation: C.A.K.E.D.-F.I.V.E., she ends up falling for Numbuh 19th Century, who is inadvertently sexist towards girls himself, and is found kissing him when they are rescued from their cell.
she tells Numbuh 4 that she always thought he was cute as she was about to decommission him .
it's revealed that is secretly a fanatic of Rainbow Monkeys and has she has a bedroom full of them. She doesn't want any boys to discover this and threatens "Numbuh Four Thirtyteen Seven" not to tell anyone.