- "You're all prisoners. What you call sanity, it's just a prison in your minds that stops you from seeing that you're just tiny little cogs in a giant absurd machine. Wake up! Why be a cog? Be free like us."
- —Jerome Valeska's speech to GCPD after its massacre[src]
Jerome Valeska is the unstable son of a snake-dancer Lila Valeska and blind fortune teller Paul Cicero. Born and raised at Haly's Circus, Jerome suffered a psychotic break at the age of 18 and murdered his mother which lead to his arrest and incarceration at Arkham Asylum. Following a breakout with other inmates by Theo Galavan he became the leader of The Maniax and brought terror upon the city. This lead to his betrayal and murder at Galavan's hands, although his death led to an underground movement being created devoted to Jerome. Jerome was later resurrected from the dead by a follower, leading to him to reign terror once again upon Gotham City.
Jerome was told by his mother that his father was a sea captain named Sven Karlsen, who died while out on sea.When the circus traveled to Kansas City at the time of his birthday, on his 9th birthday his mother along with a man both boozed, boned, & beat him up. He was crying outside the trailer when Cicero told him that the world didn't care about him and that it was better to realize it then.
Killing his mother
Sick of his mother's constant nagging, especially after she had sexual relations in the room next to his, Jerome killed his mother, and was allowed by Paul Cicero to clean up in his trailer. Jerome was then told by Cicero to scratch the initials for the Hellfire Club on the hatchet used to kill Lila, and to throw it off Arkham Bridge. Later, when Detective Gordon along with Leslie Thompkins and the circus ringmaster, came looking for Lila Valeska, Jerome answered the door to the trailer, denying knowing where she was. Gordon later had Lila's snake lead the group to her dead body, with Jerome faking despair at seeing his deceased mother. At the Gotham City Police Department headquarters, Jerome was questioned by Detective Gordon on whether or not his mother had any enemies, and how he felt about her sex life, in an attempt to discern a possible suspect. Jerome was later brought back to the GCPD on the request of Gordon, who had come to the conclusion that Jerome had killed his mother, and Cicero, who Gordon had also come to the conclusion was Jerome's father, had helped him cover it up. Vehemently denying doing such a thing, Jerome later admitted to it, laughing maniacally after Paul Cicero admitted to being Jerome's father.Jerome was later sent to Arkham Asylum for his crime.
Leading The Maniax
Jerome and several others looked on as Barbara Kean walked into Arkham for the first time. He later approached her on the behalf of Richard Sionis, attempting to persuade her that a girl needed a friend in the Asylum, as bad things happened there all of the time. Though she seduced Aaron Helzinger into being her friend, Jerome brought up the point that her new friend was a "gorilla", and that his friend, Sionis, ran the place, and could get her anything she needed. Jerome was later among the six inmates knocked out by the knockout gas that came out of Zaardon's body and abducted by Tabitha Galavan. Regaining consciousness alongside the other inmates, Jerome was formally introduced to Theo Galavan and his sister, Tabitha, with Theo offering the six inmates the chance to become a team of brilliant outlaws that would make Gotham City tremble.
Jerome and the escaped prisoners three people off a roof onto a crowded street as a way of spreading fear. The next morning, Jerome showed Theo how much of a stage present he had. While examining Theo's weaponry, Jerome got into an argument with Robert Greenwood over who would be the leader. Theo decided to settle it with a game of Russian roulette. Greenwood pulled first, and then Jerome risked his life by pulling the trigger three times, showing just how crazy he was. After that, Theo and Greenwood both accepted Jerome's leadership. The Maniax's targeted a bunch of high school cheerleaders on a bus. They doused in gasoline and planned to set it on fire, but the intervention of the GCPD forced the Maniax to retreat. Disguised as police officers, The Maniax infiltrated the GCPD. Jerome took Commissioner Sarah Essen hostage. Essen then told Jerome that he will be dead and no-one will remember his name. Jerome hissed that they will spread like a virus and asked her if she knows why. Greenwood said there is nothing more contagious than comedy, so Jerome shot him for stealing his line. Sarah headbutted Jerome, and he said it was his turn. Jerome killed Sarah and left a message, saying that they haven't seen anything yet.
Jerome's next target was his father. With Tabitha's help, he tied Paul to a chair and told him of how his mother's lovers abused him and that Paul had comforted him, marginally. He asked Paul what his future is, and Paul proclaimed that his son would be a plague among Gotham, and his legacy would leave death and destruction. Jerome killed Paul and made his escape. He and Barbara later teamed up to hold an entire room of people hostage. He dressed as a magician and Barbara was his assistant. They lured the crowd into a false sense of security and then Jerome killed the deputy mayor. Theo put on a show of trying to stop them, and Barbara pretended to hit him with a mallet. Jerome asked for Bruce Wayne, threatening to shoot his butler and guardian Alfred Pennyworth. Bruce revealed himself and Jerome held him hostage. Theo appeared behind Jerome and stabbed him in the neck. Theo apologized to Jerome and said that now he is the hero. Jerome said that Theo said he was going to be a star, but died before he could finish, with a bloody smile on his face.
Several copycats across Gotham City began mimicking Jerome's laughter after seeing him on the news, and two men even murdered a homeless man, apparently under his influence. Then one of the pair began stabbing his friend to death, thus showing Cicero's prophecy that Jerome's legacy would be death and madness is becoming a reality. Oswald Cobblepot revealed to his gang that even though Jerome is dead, people are still scared of him.
A nightclub and band run by Jeri appears dedicated to Jerome and the Maniax with attendees wearing straight jackets similar to those which Jerome and the Maniax wore when they attempted to set fire to the school bus.
Jerome's corpse was taken inside a storage warehouse along with multiple other corpses involved with Indian Hill. Dwight Pollard, who used to be an employee at Indian Hill prior to it closing down managed to learn to resurrect the dead. Dwight was also the leader of Jerome Valeska's cult. While trying to revive Jerome, he realized that the process hadn't worked and that Jerome was seemingly still dead. With the GCPD closing in quickly, he decided to "give the cult members Jerome" and cut off his face, after killing the associate that helped him, and then escaped. Jim Gordon later saw Jeromes face-less corpse laying on the operating table.
Jerome's corpse was brought to the GCPD morgue where he suddenly woke up and killed a nearby police officer, taking his gun, and also bandaged his face. Later Leslie Thompkins entered the morgue and Jerome came up behind her, took her hostage, and asked her a few questions, such as who killed Theo Galavan, whether her and Jim were still together, and if they had ever done anything with each other. Jerome then asked her where his face was and, with her not knowing the location, decided to gag her. Suddenly, Channel 9 News started broadcasting and showed Dwight with Jerome's face and Jerome proclaimed that Dwight had no charisma. Jerome then took a cop car and, after hitting a pedestrian, went to the Channel 9 News Studio. After Dwight was arrested, Jerome took his face and kidnapped Dwight, leaving in a cop car. Jerome then took him to the cities power plant. There Jerome stapled his face back on with a staple gun and, at first, was nice to a increasingly frightened Dwight, exclaiming "What's a cut-off face between friends". However, he later beat him, tied him up, laced him with explosives, and then began to broadcast a message of his own. He held a speech saying that everyone in Gotham could "Do what you want. Kill who you want". He then lit a firecracker and threw it on the ground in front of Dwight, telling him "I don't forgive you for the face" before laughing hysterically and leaving. Dwight stared blankly as the power plant exploded, killing him and putting Gotham in a city wide blackout.
Revenge on Bruce
Jerome's speech seemed to have a pretty strong effect as rioting began shortly after, with regular citizens taking his "cue". He then went to Bruce's house and began to destroy Bruce's belongings, including the Court of Owls glass statue. When Bruce asked why he was at his mansion, Jerome told him "Because I'm going to kill you". Bruce then convinced him that his death should be a public one, and Jerome then took Bruce away and told his goons to kill Alfred, however he was saved by Jim Gordon. Jerome took Bruce to a circus that his cult had taken over, and Bruce was horrified at what he saw. Jerome's cult had turned the circus's games into much darker versions of them, most of which involved hurting and/or killing people. He then told Bruce that Gotham had no heroes. He was about to throw a baseball at a button that would drop a man into a tank filled with piranhas, however Bruce pushed him. He then pushed the button, dropping the man into the tank and he was devoured by the Piranhas, much to the distress of Bruce. He then used a staple gun to staple his face back on because it was falling off. Bruce asked him if it hurt and Jerome came over and stapled his arm. To Jeromes surprise, Bruce didn't show any emotion at all so he stapled him again and Bruce once again showed no emotion. However, after Jerome stapled his arm for the third time, he yelled out and Jerome laughed. He then took Bruce over to a mirror where a cult member painted his face. Jerome then stabbed the cult member in the stomach, put his finger in his wound and then painted a frown on Bruce's face, saying "Let's turn that frown, upside down" with a laugh. Jerome then took Bruce over to the main part of the circus where a huge crowd of his cult members were waiting for "the main event". He tied Bruce up on a wooden pole with handcuffs and "entertained" his "guests". He brought a canon over and set it up so it would hit Bruce and then poured knives, nails and a canon ball into it and got ready to light the fuse. Suddenly, Jim, Harvey Bullock and Alfred arrived with the rest of the GCPD and began to arrest/kill the cult members. However, Jerome lit the fuse and ran away laughing. Bruce was able to escape, just as the canon went off, using the staples to pick the handcuffs lock.
Jerome went looking for Bruce and saw him run into a hall of mirrors and followed him. Jerome cautiously stepped into the hall of mirrors and later used all of his bullets up trying to kill Bruce, who kept avoiding Jerome. Bruce then said that he wanted Jerome to follow him and that Jerome was going to pay for what he'd done. Jerome then threw his gun down, saying that Bruce can try to be a hero and that they could fight one on one. Suddenly, he pulled out a knife. Bruce tackled him from behind and Jerome dropped the knife as he made a quip saying "What hero tackles someone from behind?". Jerome then told Bruce to "put em up" and began to bounce around, not taking the fight very seriously. Bruce brutally beat him down to the ground and jumped on top of him. He continued to punch Jerome in the face until his face literally started to come off. Jerome then told Bruce to "let it out" as Bruce continued to brutally punch him again and again as Jerome laughed. Suddenly, Bruce grabbed a shard of glass and held it up to stab him. Jerome told him to do it in order to prove that Gotham did indeed have no heroes. However, Bruce looked in the mirror and saw himself becoming like Jerome and decided to spare him. He screamed in Jerome's face and throw the shard to the side and left, leaving Jerome to lay there. However, Jerome wasn't done, and later ran at Bruce and Alfred as they hugged, holding a shard of glass. He was defeated by Jim Gordon, who literally punched his face off. It was later revealed by Harvey that he would be going back to Arkham after the doctors put his face back on. Jim jokingly asked Harvey if he would have liked it better if he had killed him and Harvey replied "No, he probably just would have come back to life again".
- Explosives knowledge: Jerome managed to create a bomb powerful enough to destroy the Gotham power plant.
- High pain tolerance/Indomitable will: Having been abused as a child, Jerome has learned to withstand physical pain. Even when Bruce kept punching him in his face, he smiled and stayed conscious.
- Leadership: Jerome was able to lead hundreds of Gotham citizens into causing havoc and chaos in the city.
- Master of Deception: Prior to revealing to true nature, he was able to trick others into thinking he was innocent of his mother's murder.
- Skilled knife-thrower: Jerome is skilled at throwing knives, such as when he threw a knife into the Deputy Mayor's chest.
- Skilled marksman: Jerome is skilled at using firearms.
- Jerome's character is a nod to The Joker, the most famous adversary of Batman. That character was created by writer Bill Finger and artists Jerry Robinson and Bob Kane, first appearing in Batman #1 (1940) as Batman's very first nemesis. In season 3, Jerome had his face cut off, which is then later reattached to his face, a nod to the New 52 Joker whose face was removed by the Dollmaker, after which he started wearing it like a mask, holding it onto his head with leather straps and metal pins (he later allowed it to grow back).