Monsters (Gotham)

"For months, I warned the police about the threats to our city, posed by Hugo Strange's freaks, by the murderer Fish Mooney, and how did they protect you? They said that Fish Mooney wasn't real, that these escapees were victims who need our help. Well, Fish Mooney was real, and once she was cornered by the GCPD, finally, they let her escape. And these "victims"-- well, I, for one, am not afraid to call them by their proper name: MONSTERS! Our city is invaded by monsters, attacking our brothers and sisters, and it is up to us! To you! To kill every monster you see! WHO IS WITH ME?!"

- Penguin encouraged Gotham citizens to hunt down Indian Hill escapees Former Arkham Asylum inmates, called Monsters due to the powers they obtained while being experimented on, serve as villains in the second and third season of the television show Gotham.

History
Secretly, Hugo Strange, the director of Arkham Asylum, is experimenting on various inmates in a secret laboratory underneath Arkham. There, he searches for a way to bring people back to death, which eventually succeeds when he brings back Theo Galavan, who he brainwashes into believing to be the ancient warrior Azrael. Realizing that the people he returned from death need a new identity in order to thrive, Strange begins creating new identities for the people he brings back. He also starts mixing the DNA of his experiments with other DNA, resulting in various powers obtained by the experiments.

However, the revived Fish Mooney, who has returned with her memories intact, highjacks a transporter supposed to deliver some of Strange's experiments to another facility. The truck crashes inside Gotham and the experiments are freed, venturing into the city on their own.

Six months later, most of these experiments have joined Fish's gang. The citizens of Gotham are horrified of the monsters inside their city and people, including former GCPD detective Jim Gordon, have started to hunt these monsters down for money. Oswald Cobblepot starts rallying the people of Gotham against the 'monsters', causing a city-wide hunt against them.

Strange's henchmen

 * Azrael: Formerly Theo Galavan, was the first person Strange successfully reanimated.
 * Mr. Freeze: Formerly Victor Fries, was turned after commiting suicide with his freeze formula. Can only survive in sub-zero temperatures. Current status unknown
 * Firefly: Formerly Bridgit Pike, was turned by Strange after having been horrifically burned. Turned into the 'fire-goddess' Firefly, but betrayed Strange after he threatened her friend Selina Kyle. Current status unknown.
 * Basil Karlo: Has the ability to shape-shift and change his voice. Used by Strange to impersonate Gordon but was arrested when he was revealed as a fraud.

Fish's gang

 * Fish Mooney: A former crimeboss, revived with her memories intact. As Strange fused her DNA with cuttlefish DNA, Fish has obtained the person to influence people by touching them, making them do whatever Fish orders them to do. However, the use of her powers slowly kills her.
 * Marv: One of the experiments that was not turned by Strange but his assistant Peabody. Has the ability to age people by touching them, causing them to die of old age if he touches them long enough.
 * Nancy: Skilled fighter, other abilities unknown. Wears a facial mask. Killed by the people of Gotham along with Sid while covering Fish Mooney's escape.
 * Sid: Has the ability to run incredibly fast. Killed by the people of Gotham along with Nancy while covering Fish Mooney's escape.
 * Bat-like man: An agile man who has the ability to grow bat-like wings. Was arrested by Jim Gordon while attempting to kidnap Ethel Peabody.
 * Electro woman: A woman with the powers to create electricity from her hands. Last seen fighting GCPD officers in the old bank.
 * Scale Skin Man: A man with a green skin and scales. Last seen fighting GCPD officers in the old bank.
 * Ridgeback Monster: An incredibly strong but slow monster with ridges on his back. Killed in battle with Jim Gordon when he stumbled onto a street and was run over by a truck.
 * Person whose touch burns: A person whose touch causes pain and burn marks on the body of the touched person.
 * Bearded Man: A bearded man seemingly impervious to bullets.
 * Various monsters whose powers have not been shown yet.
 * Selina Kyle: Member of Fish's gang, but not experimented on by Strange.

Others

 * Bruce Wayne-lookalike: A mysterious boy, looks like Bruce Wayne albeit with long hair. His identity and agenda are currently unknown
 * Karen Jennings: Was one of Strange's experiments when he ran Pinewood Farms. Her arm was turned into a bird-like talon. Died while defending Bruce Wayne against Mr. Freeze.
 * Jerome Valeska: Was one of the dead people revived by Strange. He escaped into the city when Fish's van crashed but has not joined her gang and has not been seen since.