Originally, Fish Mooney was just an add-on character who was never meant for a major role, but landed right in the center of our hearts which occured just a bit like Dr. Harleen Quinzel.
For those who have not yet began to watch [Gotham](series:1127075) on the Fox TV network, you're in for major spoilers! When we are introduced to the characters of our sad, yet great, city of Gotham, we are met with many familiar (and young) faces such as the Riddler (Dr. Ed Nygma), Comissioner Gordon (here only a young detective), Selina Kyle (Catwoman), Young Ivy Pepper (Posion Ivy), Carmine Falcone, Oswald Cobblepot (the Penguin) and many, many more! However, we then are also introduced to a young beauty who left us all wondering who exactly she was and where she fits in.
Fish Mooney was just one of many of Falcone's prodigy children. We learn she has set her heart out to dethrone Falcone, and finally take what she believes is her throne. It was she who adopted young Oswald Cobblepot and tought him the sneaky ways of underground deals, dirty deeds, and the maneuvering of all which makes Gotham what we know it to be today.
She took Oswald under her wing and made him (Cobblepot) her right hand man. She failed to realize the young penguin she was raising would soon dethrone her.
We soon discover how Harvey Dent (Detective Gordon's partner in crime) and Fish Mooney together work to reap their own benefits. Harvey gets all the dirty information from Mooney, Mooney has certain officers looking out for her. Its a fair game.
After Cobblepot betrays mooney, she is soon faced with death or exile (while maintaining a new secret identity because most believe her to be dead), she chose exile. Fish Mooney awakens in a basement-type prison after being attacked (we see little of this attack that happened while she is leaving Gotham in exile). When she awakens we realize that she is in a place where you come in, but never get out.
Knowing the great Mooney we know and already love at this point for being the great survivalist she is, we later llearn that she takes over this prison and soon makes her way to the top. Only to meet with a new threat. The Doll Maker (Dr. Dolmacher [a plastic surgeon who sells organs and operates on people and limb replacement surgeries]).
She earns his trust, but only to re-learn that she is never going to escape, because she is trapped in the middle of an island surrounded by freezing water for miles and frozen mountains just a bit after that. What will become of Fish Mooney, a character never meant for Gotham, but who we now love and welcome to the DC Universe?