- "I was waiting for him to come home. We’re bound together, he and I. It's the one thing I knew for certain, the one thing I knew was true. And then he just... abandoned us. Do you know how it feels to have the one, the only thing you love ripped away from you?"
- —Jeremiah Valeska to Jim Gordon[src]
Jeremiah Valeska is one of the largest threats to face Gotham City. He is also the more obsessive and narcissistic identical twin brother of the nihilistic cult leader, Jerome Valeska.
Supposedly suffering from years of abuse at the hands of his demented brother, Jeremiah was sent away from Haly's Circus where he enrolled in St. Ignatius. After graduating Jeremiah became a very skilled and intelligent engineer experienced in many branches, but he spent most of his years hiding in fear of his brother under the name Xander Wilde, knowing he would eventually come for him. After Jerome's death and being exposed to his altered chemical laughing toxin, Jeremiah became an anarchist and the arch-nemesis of Bruce Wayne, who he idolized as his necessary opposite.
He reduced the city to ruins, elevating himself to the status of a legend within the criminal underworld of Gotham City. His growing obsession with Bruce eventually sent him careening into a vat of chemicals during a brawl. He was severely disfigured and pronounced braindead, but resurfaced over a decade later more insane than ever, having trouble differentiating reality from fantasy in his past memories. He eagerly awaited Bruce Wayne's return to Gotham as the city's Dark Knight.
At least according to Jeremiah, Jerome would abuse and scare Jeremiah when he was little. Jeremiah would later recount that he realized Jerome was dangerous and knew he needed to get away from him so he snuck away one night from Haly's Circus and had his uncle Zachary place him at St. Ignatius. Shortly afterward, Jeremiah took on the alias of "Xander Wilde". He himself would later explain that he did this in the hope of making it more difficult for Jerome to track him down.
Jerome, on the other hand, claimed that Jeremiah only made his mother believe that Jerome tried to kill him and stories about him holding a knife to his brother's throat or trying to light him on fire were made up. However, Jeremiah would later agree that some of these things didn't happen exactly as he said. According to Jerome, Jeremiah was the one who was responsible for his brother's madness by essentially creating him, giving him his 'one bad day'. Jerome stated that Jeremiah got adopted by rich people after Lila hid him away.
He would then enroll to and graduate from school, eventually becoming an engineer. Four years after graduating, he started construction on his hideout, an underground maze bunker in a forest on the outskirts of Gotham City. The building took 6 years to complete.
At an unknown point in time, he met a woman named Ecco and hired her as his proxy and assistant.
Reunited With Jerome
Ten years after Jeremiah's graduation and six years after he had finished construction on his secret office, Jerome breaks out of Arkham Asylum and kills their uncle Zachary at the diner he owns for the location of his brother.
Jeremiah is then confronted by the stunned Captain Jim Gordon and Detective Harvey Bullock. They ask Jeremiah about his relationship with his brother. He tells them Jerome had made attempts to kill him, so he fled and changed his name to Xander Wilde. Bullock and Gordon then find out that he‘s holding Jerome captive, so they immediately order Jeremiah to let him go, only for him to refuse. After finding out that the Legion of Horribles is inside the building and Ecco has been hypnotized, Jeremiah takes Jim and Harvey into the halls of his house, which were built like a maze that he only knows the way out of. The three find Ecco in the building but due to her hypnotized state, she gets into a fight with them. Ecco easily wins and attempts to take Jeremiah to Jerome, only to be knocked out by Jim. Jeremiah then tries to escape but Jerome finds him. They have a verbal fight, in which Jerome tells he’s disappointed by what Jeremiah told about him, since, in his point of view, all of the things he said were lies. Jeremiah did agree that certain things that he told were in fact exaggerations of the truth. Jerome also tells Jeremiah that he’s going to drive him crazy and then kill him. Jim and Harvey eventually get to them, so Jerome runs away leaving Jeremiah behind. Jeremiah is later taken to the GCPD so that he can be put into protective custody. Jerome took the Mayor, his wife, and the police commissioner hostage. He demanded that Jim bring him, Jeremiah and Bruce Wayne. Jeremiah is hesitant to go at first but later agrees. Jerome straps Jeremiah and Bruce into a chair. Jerome tells the crowd the story of him and Jeremiah and then cuts Jeremiah free. Determined to prove Jeremiah is just like him, Jerome hands Jeremiah the knife and tells him to take his best shot. Jeremiah tries to stab Jerome, who knocks him out with a single punch. Later, Jeremiah approaches Jerome’s body after he fell to his death. As Jeremiah walks away, Bruce asks him to let Wayne Enterprises fund his work. Jeremiah thanks Bruce and shakes his hand.
Birth Of A Madman
- "..My days were numbered, but you can continue on for me, be my ultimate revenge!"
- —Jerome Valeska announcing his legacy in a recording for Jeremiah[src]
Revealing His Dark Side
Jeremiah created a recording tape of himself disguised as his deceased brother Jerome and stated that he would have a wake at the GCPD. He then set Ecco to invite Jerome fanatics that were celebrating at his grave.
When Bruce Wayne visited Jeremiah Valeska, he showed Bruce Wayne the prototype of the device he was working on. He also pulled out Jerome's diary which Arkham gave to him after his death. There he revealed that the book was disturbing and holding him back but Bruce morally supported him by saying to quit the book. Shortly after, Bruce received a phone call about Jerome's wake and Jeremiah became paranoid. Jeremiah confessed that he was sprayed the Insanity Gas as Jerome's last sick game and Bruce convinced Jeremiah to visit Jerome's grave to truly convince the cowering Jeremiah that he was truly dead. After visiting the grave and finding it empty, Jeremiah runs away inside the cemetery building and when Bruce catches up to him, it appears as Jeremiah is losing his mind, now that he views that Bruce is his dead brother.
After Jeremiah chases Bruce towards Jerome's Graveyard, Jerome's body is now placed next to the tombstone. Still not buying the fact that his brother is dead, he pulled out a knife from Jerome's corpse and fought Bruce Wayne. Jim Gordon investigates the bunker and a recording starts playing. when Ecco arrived and placed a gun at his head, the recording starts and it looked like Jerome had an extra tape regarding Jim Gordon. After an extensive fight with Ecco, it is revealed to Gordon that Jeremiah was faking the Jerome act as he peels off the fake damaged skin and rubs the makeup off with a cloth.
Meanwhile, after a thug proclaims proudly "Jerome is victorious at last" Jeremiah murders him in cold blood due to him believing that he was the victorious one and not his brother since he was dead. Now cold and monotone, Jeremiah wiped the blood of his victim off his face, along with the makeup disguising his altered features; he apologizes for the act, saying it was to show Jerome's followers what an utter dud his brother was.
Kicking Jerome's corpse into the grave, he then revealed his plans for Gotham as he pulls out the diary and states he is going to outdo his brother’s goals in a sane matter. Bruce disregards his plan, saying it's complete madness and to carry out Jerome's plans in a "sane" manner. Jerome replies with an entry from Jerome's diary: "Jerome wanted to slather you in honey and have you eaten alive by corpse beetles - me, if I wanted to kill you I'd just do it." However, Jeremiah then said he didn't wish to kill Bruce, as he truly does see him as his best friend. He then reveals to Bruce and Gordon that the generators he invested his money in can double as highly powerful bombs. Back at Jeremiah's residence, the bunker's generator starts to overload, but luckily Jim finds a secret buzzer underneath the table and unlocks the door and escapes the bunker before it explodes. Jeremiah and Bruce both presume Jim has died, and Bruce angrily vows that he will stop Jeremiah. Jeremiah knocks him out and drops him into the grave with Jerome's corpse.
Jeremiah and Ecco then head to Wayne Enterprise and kill two guards to obtain their keycards. they open the locked door with the key cards and it is revealed that there is a room full of the power generators Jeremiah created and Bruce invested in. He then orders Ecco to move them as he plans to destroy Gotham and "Rebuild it." 
Plan To Rebuild Gotham
- "I'm going to create a new Gotham in my image, but every artist needs a blank canvas so all of this has to go"
- —Jeremiah Valeska to Harvey Bullock[src]
Jeremiah gives Bullock six hours to evacuate the city and destroys the Gotham Clock Tower to show he is telling the truth. Shortly afterward, his men are shown knocking out and capturing Alfred Pennyworth at Wayne Manor.
Later, when Bruce meets with Bullock, Jeremiah calls him and tells him the address Alfred is at and warns Bruce not to tell the police as Jeremiah knows where Bruce is. Allying with Scarecrow, Jeremiah later watches Bruce via CCTV as he is sprayed with Scarecrow's fear toxin and forced to witness Alfred being tortured in an attempt to drive him mad. Jeremiah remarks that he "envies" Bruce having a "transformative experience" and that he wants him to be able to embrace his true, darker nature after being forced to lose everything and everyone he loves.
As Jeremiah enters his safehouse, he finds The Penguin, Barbara Kean, Tabitha Galavan, and Butch Gilzean waiting for him with one of Jeremiah's henchmen, Jongleur, hostage; they have also located and taken the core relay that allows him to detonate all his bombs at once. They demand an additional hour to evacuate the city and $50 million. Jeremiah, knowing they will double-cross him anyway, pretends to agree to their demands and calls the mayor, but then claims he was put on hold, pulls out a bazooka and blows up Jongleur and the core relay. Furious at Penguin's assertion that he is "out of his mind", Jeremiah remarks that he has always had a backup plan and can simply detonate the bombs in sequence instead. He then tells them he has changed his mind about the deadline due to their interference, and will detonate the bombs as soon as he's a safe distance away. Jeremiah orders his followers to "kill these idiots" and escapes during the subsequent firefight. Arriving at another bunker where the Cult of Jerome are gathered, Jeremiah prepares to detonate the bombs, but it's suddenly revealed that Gordon is still alive, much to his fury. Jeremiah triggers the detonator for the first generator, but it doesn't explode as Bullock found and disabled it just in time. The Cult of Jerome gets angry at Jeremiah, calling him a liar and a fake; he reacts by sealing them inside the bunker and incinerating them, saying he anticipated their betrayal. All but one of Jeremiah's generator bombs are retrieved by the GCPD, while Bruce is able to rescue Alfred and overcome Scarecrow's fear gas with the help of Selina Kyle.
Later, hiding out alone at an abandoned theater, Jeremiah wonders aloud how he was defeated; he concludes Gordon must have found his maze blueprints and sabotaged the sequence by finding and disarming the first bomb (which is almost correct, except for Harvey Bullock being the one who disarmed the bomb). As Jeremiah decides he must start over, he is interrupted by the appearance of Ra's al Ghul, who compliments him on his tenacity and suggests they can cause the destruction of Gotham together. Jeremiah sarcastically replies that "recent events have convinced me of the benefits of working alone" and tries to shoot Ra's, who easily evades his bullets. Realizing that his attempts to kill the Master of the League of Shadows are futile, Jeremiah reluctantly hears him out. Ra's explains that Jeremiah's plan for a "new Gotham" can still come to be with the help of the League of Shadows, and both their plans are not just about Gotham, but about Bruce Wayne, which draws Jeremiah's interest.
Later at Wayne Manor, Bruce and Selina are talking about Jeremiah's obsession with Bruce. Bruce explains that Jeremiah was working on the premise that "one bad day" can drive someone insane. He wonders if the trauma of his own parents' deaths "made him a little insane", and if Jeremiah had sensed that and was trying to bring it to the surface. As Selina replies that Bruce proved him wrong, Jeremiah suddenly enters the room and holds a pistol to her abdomen, remarking that the day's not over yet. He shoots Selina in the stomach, knocking her backward, then smiles and throws his gun away. As Bruce desperately tries to keep Selina alive, Alfred rushes in, knocks Jeremiah down and begins pummeling him repeatedly in the face. 
Aligned with Ra's al Ghul
- "I didn't yet understand the vision I was servicing, but I do now, my eyes are open, as will yours be."
- —Jeremiah Valeska to Jim Gordon[src]
After being arrested, Jeremiah is held at the GCPD. Talking with Gordon, Jeremiah mockingly says he wishes to press assault charges against Alfred for punching him in the face, to which Gordon (with equal sarcasm) replies that he thinks Jeremiah looks just fine, ordering Harvey to prepare to transport him to Arkham. Jeremiah offers to give up the location of "other" bombs he claims to have planted around the city, in exchange for being allowed to speak alone with Bruce. A few moments later one of his generator bombs (planted by Ra's al Ghul) goes off and destroys City Hall, killing the mayor and seemingly confirming that Jeremiah is not bluffing. Gordon attempts to beat the locations of the other bombs out of Jeremiah, who barely reacts, merely grinning and humming "Ode to Joy". A major finally has Bruce Wayne meet with the restrained Jeremiah, attempting to get the location of the other bombs. Jeremiah excitedly urges Bruce closer, suggestively, then admits that he believes Bruce is his kindred spirit. He goes on to taunt him about Selina's injuries in a show of jealousy and amusement. When pressed about the location of the "other bombs", Jeremiah reveals that the only other bomb was the one he used on City Hall.
Jeremiah finally reveals to Bruce he is working with Ra's al Ghul. The lights suddenly go out, during which several guards are killed and Bruce and Jeremiah both vanish; they have both been evacuated from the GCPD by the League of Shadows, which also steals all of Jeremiah's confiscated bombs and re-distributes them across Gotham's bridge system. The League then brings Jeremiah and Bruce to an abandoned building overlooking Gotham River, where Ra's is waiting for them. Ra's and Jeremiah tell Bruce they'll create a legacy by destroying Gotham, allowing Bruce to be "reborn" as the Dark Knight of Ra's visions. Jeremiah admits he is skeptical of prophecies and visions, but the idea of he and Bruce rising out of the fall of Gotham together appeals to him.
Shortly after, Barbara Kean, wielding Ra's cursed knife, arrives, referring to Jeremiah as a "freak". At first they think Barbara came alone, however, Penguin then started screaming and shooting a machine gun at the League, while the whole alliance of Tabitha Galavan, Alfred Pennyworth and the Sisters of the League appeared behind him and began battling Ra's al Ghul's men. Ra's defends himself against Alfred and Barbara, asking her if she will never learn, but she finishes the sentence for him, telling him she gets that the knife has to be held by Bruce Wayne only. Jeremiah uses Bruce as a shield and shoots a member of the Sisters of the League, but Tabitha's whip ties his hands together and pulls him away from Bruce. Galavan then laces her whip around Jeremiah's throat, trapping him in a stranglehold and forcing him to his knees in front of her. She tells him "this is for Selina", but before she can deliver a killing blow, Valeska manages to draw Tabitha's own knife and stab her in the leg. Valeska then grabs Galavan, throws her on the ground and grabs her throat with one hand, holding her knife near her eye with the other, smiling sadistically while telling her that it must be very disappointing for her to die like this in case she wanted to avenge Selina. However, Valeska is suddenly shot in his shoulder by the Penguin. Surprised that Cobblepot, of all people, saved her life, Tabitha looks at him in confusion; she doesn't know yet that he has his own reasons for keeping her alive. After knocking out Palden, Bruce turns to fight Ra's, but both he, Barbara and Alfred are kept at bay by the Master of the League of Shadows. While Ra's is fighting Alfred, Barbara forces the knife into Bruce's hands before ramming it into Ra's stomach. Jeremiah, still lying on the ground with an injured shoulder, watched this with surprise. As Ra's body began to disintegrate, he looked at Barbara Kean, saying "Well done, Barbara".
Right then, the sound of an explosion shakes the whole city, drawing the attention of Barbara, Bruce and Ra's, as well as the horrified Oswald Cobblepot and Jeremiah Valeska, the latter one smiling savagely as one of Gotham's main bridges collapses into the Gotham River. Multiple other bridges follow the same fate, crashing into the water after their connections to the mainland give in to the detonation of Jeremiah's generator bombs. Shocked by this sight, Penguin, Barbara, Tabitha, Bruce and Alfred witness power failures affecting the fallen city. The dying Ra's grabs Bruce's shoulders, looking into his eyes and telling him that the choice is now his: he can either stay Bruce Wayne or accept his destiny and become Gotham's dark knight. With that, Ra's al Ghul's body disintegrates, leaving only the knife behind. Horrified, Bruce turns to face the destruction of his city. By this point, Jeremiah Valeska has already taken advantage of the confusion and escaped. The alliance against him had failed to prevent the city's downfall.
Shortly afterward, Bruce is seen interrogating a small-time criminal about Jeremiah's whereabouts; he tells him to let Jeremiah know he is coming for him.
No Man’s Land
Jeremiah remained hidden, but at some point had Ecco prove the extent of her loyalty to him by shooting herself in the side of the head. He had the Soothsayers digging underground while he sent Ecco out to gather new recruits to join them by establishing the Church of Jeremiah Valeska. Ecco is sent to the GCPD to spy on Jim Gordon, where she knows more than Jim lets on. She then leaves graffiti with Jeremiah's laugh symbol on the map of Gotham, and reports back to Jeremiah to report on events Jeremiah has not witnessed, such as the death of Tabitha, (Indicating that she will not be a danger to him anymore) and the explosion of the Wayne supply helicopter. Unbeknownst to Jeremiah, Lucius Fox had taken one of Jeremiah's disabled power reactors and modified it to be utilized for its original use: As a power supply, this time supplying the GCPD with a backup energy source.
No Man’s Land: Day 96
Sykes approaches Jeremiah, telling him that he is working his men too hard and they won’t break through for at least another two days. Jeremiah responds by slashing Sykes’s throat and says they won’t get anyway with that attitude. Jeremiah addresses the Soothsayers as their new leader and says to dig a little deeper because that’s the only way they are making it out. Jeremiah is busy laughing and arguing with himself about a gift that someone’s going to love when Ecco returns with the new recruits. Jeremiah clears his throat and composes himself. He askes Ecco if those are all the new recruits, and she said she thought he would want quality over quantity since not everyone can pass a high caliber test of faith.
At first, Jeremiah grabbed Ecco around the throat, seemingly out of anger, but then pulled her close to examine her scar. He agrees that she has set a very high bar for devotion, and then pulls her into a dance. As they dance, Ecco tells him about Bruce and Selina, and that Selina can walk and is out to kill him. Ecco says if she sees Selina she will tell him and then adds that she will kill her. Jeremiah smiles at Ecco and sends her away with one last twirl before turning away as Ecco walks away with the recruits.
Jeremiah is fanning himself with his hat while “encouraging” the Soothsayers to continue digging. He compares their efforts to a river due to persistence and has them chant that they will dig a little deeper to each of his questions of persistence. "Ecco" returns and abruptly stabs Jeremiah, who looks shocked until she removes her mask to reveal Selina’s face. Selina asks Jeremiah if this is deep enough for him. Jeremiah rasps that he must say, but Selina stabs him again and tells him not to say anything. She then stabs him seven more times and raises the knife before Bruce stops her. Jeremiah falls to the ground and the Soothsayers attack Selina. Alfred intervenes and throws a smoke grenade while Jeremiah lies on the ground with his eyes open, apparently dead. In reality, he had faked his death because he knew that Bruce and Selina were on his trail, not yet ready to unveil his plans.
Continuing His Plan
Jeremiah is later found, resting on a makeshift bed while his followers continue digging. As soon as they break through, Ecco runs to wake up Jeremiah. She shakes him and Jeremiah says "Ouch". Ecco notes that the stitches were still sore and that this wouldn’t have happened if he wore that armor she prepared. Jeremiah says that the bullet was making her sentimental and orders Ecco give her head a shake. Ecco shakes her head and Jeremiah asks if she was better. Ecco nods yes, and helps Jeremiah as he gets up. Jeremiah reminds Ecco that he had told her that he had to let Selina thrust the knife into him at least once to make it look real which trumps precaution for him. Ecco says she understands he had to let Bruce and Selina think he was dead in order to continue the plan without Bruce and Selina being on his tail.
Jeremiah suddenly grabs Ecco and tells her he takes it that she has news. Ecco says all systems go, and Jeremiah impatiently tells her to lead the way. He grabs a lantern and stumbles after Ecco, who leads him into what looks like Wayne Manor where two people sit wrapped in bandages. Jeremiah tells the doctor that he is hearing good things, and the doctor says the bandages are ready to come off, and says his assistant thought he would like to see the results for himself. Jeremiah says he would, and waits as the doctor unveils the bandages. Jeremiah laughs and says they look beautiful. He walks closer to them and says he loves family reunions.
Later, when Alfred is the street at night, Jeremiah surprises him and knocks him unconscious. Alfred wakes up in Wayne Manor to see Jeremiah. After Alfred threatens Jeremiah if he touches Bruce, however, Jeremiah answers “Today is the big day.” 
Ace Chemicals Incident
- "You need me! I'm the answer to your life's questions! Without me, you're just a joke... without a punchline."
- —Jeremiah Valeska to Bruce Wayne[src]
Bruce is then led by Jeremiah to the theater where Thomas and Martha had shown him The Mark of Zorro, showing him his own recreation of the past theatric production where Jeremiah is "the star of the show". He taunts Bruce about how he left the theater because he was afraid during one scene in the film. However, he then gets "Thomas" and "Martha" to leave the theater using Tetch's commands, causing Bruce to follow them.
While Bruce is still looking for them, Jeremiah finds out about Jim Gordon and Lee Thompkins infiltrating Ace Chemicals and that Tetch was able to hypnotize them. He decides to use them as replacements for Bruce's parents in the alley and shoots the lookalikes, believing that killing Jim Gordon would be like killing Bruce's second father and killing Lee would be like killing one of Bruce's closest friends. He continues to prepare his plot in the alley where the real Thomas and Martha died.Bruce arrives at the alley, and Jeremiah tells him to step back as he holds a gun, ready to shoot Jim and Lee, who has a pearl necklace like that of Martha Wayne, keeping them hypnotized until the pearls break. He explains how he seeks to be bonded to Bruce more than just some random mugger who shot his parents before he reveals that he now has Lee and Jim under Tetch's control instead of his parents, which concerns Bruce. Jeremiah also prepares Ecco with enough chemicals preparing to launch that the mainland will never help Gotham. The murder is interrupted by Selina pouncing from the fire escape. Leading to Jeremiah starting his plan early and ordering Ecco to activate the chemicals. Leaving that for Gordon to handle while he baits Bruce to Ace Chemicals. They have a face-off where Jeremiah gets extremely desperate in trying to prove his point, taunting Bruce by asking if he feels a connection between them and how Bruce needs him. Jeremiah doesn't seem to fight back when Bruce begins to continuously punch him until Bruce states that Jeremiah is nothing to him. When Jeremiah gets the upper hand, he knocks Bruce into a railing and begins to continuously punch Bruce until he ducks one of Jeremiah's punches, causing Jeremiah to break the railing and fall into the chemicals below.
Jeremiah is later recovered but is found comatose, severely disfigured as a result of the chemicals. Though Selina is surprised that Jeremiah managed to survive the incident, Bruce claims that he has no brain activity and is no longer a threat to them or Gotham.
Despite being comatose, Jeremiah still affected some of the events of No Man’s Land indirectly. His toxic chemicals mutated some of the civilians into ravenous monsters, and Ivy Pepper decided to use the chemicals to poison all of Gotham. Bruce later decided to use one of Jeremiah’s generators to knock down Wayne tower in order to stop Bane’s forces from advancing to the GCPD. Lucius was able to make the device more efficient when he managed to separate the core and the activator from the majority of the reactor, thus allowing it to be carried and utilized much more efficiently.
10 Years Later
Planning to Destroy Wayne Tower and Framing Harvey Bullock
Sometime after falling into a vat of chemicals, Jeremiah is sent to Arkham Asylum and he awakens from his comatose, however, remains in a fake comatose, seeing no reason to take any actions until the one person he was obsessed with, Bruce Wayne, finally returned to Gotham.After Bruce manages to return to Gotham after a decade, Jeremiah finally takes action and creates a plan to blow up the newly constructed building, Wayne Tower, at its opening party by getting a security guard to obey his orders as well as kidnap Edward Nygma and help him escape Arkham Asylum. In Arkham Asylum, Jeremiah is seen in a wheelchair with severe scars on his face and minor strands of hair remaining on his head, with another inmate moving a paintbrush along the remaining hairs on Jeremiah's head. However, Nygma intervenes, telling the inmate that this was Jeremiah Valeska and that even if he can't think or feel anything, he is still a legend, before telling the inmate that if he's gonna screw with a legend then he has to do it properly, breaking the paintbrush in half and stabbing Jeremiah in the leg with half of it. Despite this, Jeremiah remains still and doesn't do anything. Shortly after, an alert in the Asylum occurs as inmates are taken, with Jeremiah being taken by Ecco, who is now a nurse at the Asylum, and Nygma being taken by apparent guards, who work for Jeremiah. After the GCPD begins to search for Edward, Harvey Bullock and Vanessa Harper discover the address of a guard who didn't show up for work and as a result, Harvey decides to travel to the location of the guard. As Harvey enters the home of the guard, he is knocked down to the ground by the guard, who tells him to keep his mouth shut and talk to the man on the phone, Jeremiah. As Harvey is frightened to discover the return of Jeremiah after a whole decade, the guard aims a gun at his head and shoots himself, claiming that he didn't have a choice. As a result, Harvey is framed for murder by Jeremiah and out of fear, Harvey plays along with being framed, claiming that he's guilty to Jim Gordon, however, the rest of the GCPD doesn't seem to believe this.
As Edward wakes up in an old warehouse, he finds himself in an old warehouse and faced with a letter, stating to be from Oswald Cobblepot, however, it is revealed that Jeremiah left the note in order to manipulate Edward into using the bombs left for him to destroy Wayne Tower. When Gordon is faced with an enraged Oswald Cobblepot at the Gotham Docklands, he tells Oswald that he doesn't need to attack the Wayne Tower in order to kill him, however, Oswald doesn't seem to have any clue as to what Gordon was referring to, helping Gordon piece everything together and see that Jeremiah Valeska was behind this all. When Gordon stops a police officer from arresting Harvey Bullock, he asks if the person who framed him was Jeremiah Valeska, before the police officer tries to attack them. After defeating the officer, they check if the officer has a wire under his shirt, which he does have, leaving Harvey in immediate fear of what Jeremiah will do.
Becoming Mr. J and Reunion with Bruce
- "I feel something new, crawling from the primordial ooze that was me. Something... beautiful."
- —Jeremiah Valeska to Jim Gordon[src]
Later, Ecco is watching an Asylum guard talk to an inmate about how much it would cost to harm Jeremiah in Jeremiah's cell. However, Ecco manages to slit the guard's throat and stab the inmate in the gut, killing them both and telling Jeremiah that their cover was blown, which causes Jeremiah to giggle and grab Ecco by the throat, surprising her. When Barbara Kean and her now 10-year-old daughter returns to her old nightclub for Barbara retrieve a gun from a drawer, she is faced with Jeremiah and Ecco. As Barbara is unarmed by Ecco, who holds a knife to her throat, Jeremiah claims that this was just a surprise party for Barbara Kean, calling her the Queen of Gotham. Jeremiah states that there was another Barbara and claims that holding on to what's real is enough to drive someone mad, before Barbara Lee throws an item at Ecco, giving Barbara the chance to stab Ecco. As Barbara attempts to harm Jeremiah, he shoots Barbara Kean, knocking her to the ground and picks up Barbara Lee, telling Barbara Kean that her daughter has the same eyes as her. When he turns to face Ecco, he notices Ecco holding her bleeding stomach, and stares at her while also briefly glancing down to assess how injured she is. Jeremiah tells her that she is no longer his sweet Ecco and that there will never be anyone else like her, which surprises and excites her before Jeremiah shoots her and a large amount of blood comes out of Ecco's mouth. After Ecco dies, Jeremiah states that "there are other fish in the sea" and tells Barbara Kean that Gordon is probably searching her apartment, telling her to leave a message for him. After Gordon finds a deceased Ecco and a scared Barbara Kean on the ground, she tells him that he took Barbara Lee and that Gordon needs to go to Ace Chemicals or else he kills Barbara Lee.When Gordon finally arrives to Ace Chemicals, he discovers that Barbara Lee is dangling over a chemical vat, with duct tape over her mouth and that she was tied to a rope, being held by Jeremiah. As Gordon aims a gun at Jeremiah and slowly walks towards him, Jeremiah talks about how it's funny being in the place where he was born again, claiming that he can feel his flesh sizzling as it melted away. Gordon tries to reassure his daughter by telling her that everything will be fine, however, Jeremiah claims that everything is far from being fine. When being asked why Jeremiah is doing this, Jeremiah replies by asking if there's a Jeremiah there, before Gordon asks what to call him. Jeremiah replies by stating other names such as Jack, Joseph, John or J and that he feels something entirely new than who he was before the Ace Chemicals incident, stating that he feels something beautiful. As the two talk about why Jeremiah finally took action after a decade of pretending to be braindead, Jeremiah says that he was waiting for Bruce to come back to Gotham and that the two were bound together, before asking about how it feels to have the one thing that you love ripped away from you (referring to Bruce) then lets go of the rope that held Barbara Lee above the chemical vat,. However, Gordon manages to grab the rope and keep her up, being stabbed by Jeremiah in the process. Suddenly, he is hit with a sharp ballistic implement, knocking the knife out of his hand, before he asks whoever is there to reveal themselves. After Jeremiah takes a pause and recognizes Bruce Wayne, overjoyed that Bruce had finally arrived, Jeremiah simply laughs maniacally even when being slashed with the sharp implements but falls unconscious as one slashes his head.
Though he appeared to be more stable than his brother, calling him after his transformation a “Short-sighted psychopath" who "just wanted to destroy things”, Jerome claimed that Jeremiah was as crazy as he was. He was shown to be deceptive, as he claimed that Jerome had always been trying to kill him, though he later admitted to Jerome that it didn't happen exactly as he had described it. He tried to deceive Jim Gordon and Harvey Bullock that Jerome could not find him, even though he had already captured Jerome. He was overconfident, bordering on arrogance, on being able to keep his brother trapped, something that led to Jeremiah escaping and confronting him. Jeremiah was also willing to let people die if it meant he could avoid Jerome, showing that he was obsessed with his own self-preservation. Despite this, he refused to leave Ecco behind, saying "she dedicated her life to him" when Jim and Harvey wanted to evacuate him. He also agreed to confront Jerome after receiving praise and a few words of wisdom from Bruce. Regardless of whether or not his reluctance to leave her was out of care or because he owed it to her due to her loyalty, he only agreed to leave his bunker when they promised to return for Ecco. He appeared to show great relief when he saw her and realized she was unharmed, but it is unknown if his relief was out of genuine care for her or if he was afraid of losing one of his greatest defenses against Jerome.
After being exposed to Jerome's altered laughing toxin, Jeremiah initially appeared to have been driven completely insane, laughing uncontrollably as he was transformed by the toxin. However, according to Jeremiah, his brother’s gas did little more than alter him cosmetically. Whether he was fully insane before the gas or if he is simply attempting to downplay his brother's effect on him is still unknown; his prior behavior did hint at some repressed mental instability, which Jerome's gas may have helped bring to the surface. Gordon theorized that, by destroying Gotham in such a way that it would form a "maze", Jeremiah was turning the city into the same environment he had always felt safe in, indicating that Jeremiah's mental instability may have originated from his years of hiding from Jerome, alone and underground.
Jeremiah has still shown himself to be highly skilled at deceiving people before and after his transformation, as he was able to act perfectly as Jerome on videotapes of his "will" and deceive Bruce Wayne into thinking he was having a mental breakdown, only dropping the act to illustrate his new sinister personality. Jeremiah has also shown to be quite calm for the most part, carrying out ruthless actions without the hysterical laughter and manic behavior displayed by Jerome; his mental illness has not affected his brilliant intellect, and he does seem somewhat more in control of his actions. However, he is easy as ruthless and cruel as Jerome if not more so, indicated by his casual destruction of Gotham's clock tower just to prove a point, and his shooting Selina Kyle and torturing of Alfred Pennyworth just to "release" Bruce Wayne from everything he loves. While Jeremiah was always deceptive, this degree of ruthlessness was never shown before his encounter with the gas.
Unlike his highly impulsive brother, Jeremiah continued to plan carefully and methodically after his transformation. Whereas Jerome always felt the need to have an audience to whom he could display his schemes and sociopathic tendencies, Jeremiah did not care in the slightest about having an audience; he was always focused on his endgame and usually had a backup plan, making it much harder to anticipate and defeat him. Also unlike Jerome, Jeremiah had more of a long-term vision, describing himself as a "builder" and "artist" and wanting to create something out of his destruction of Gotham, whereas Jerome only wanted destruction for destruction's sake.
However, despite appearing calmer than Jerome, he does sometimes display the same explosive temper when his plans are interfered with, screaming at his followers to prevent them attacking him, which led to him burning them all to death. He also shows a partial denial about his insanity, as he claims he is not insane several times and becomes enraged when anyone (other than Bruce Wayne) says otherwise. Like Jerome, he is something of a masochist after his transformation, being mostly immune to pain and merely grinning when taking a beating from Alfred and later Jim Gordon.
Jeremiah has also shown two significant obsessions. The first is surpassing his brother in every way, including carrying out his various schemes to destroy Gotham but more efficiently and on a greater scale. Jerome was the one thing Jeremiah always feared the most, and after his exposure to Jerome's gas (which was derived from a variation of Scarecrow's fear toxin) his need to surpass his brother could be his way of overcoming that fear. The second obsession is Bruce Wayne, who Jeremiah views as a kindred spirit and his "very best friend" and is the only one to whom he (inadvertently) admits his insanity. Believing that Bruce's parents' deaths had caused similar mental trauma, Jeremiah makes many attempts to bring that darker nature to the surface, just as Jerome had to him. However, unlike Jerome (who was similarly obsessed with Bruce Wayne) Jeremiah makes it clear he has no intention of killing Bruce. After allying with Ra's Al Ghul and learning of his plans to transform Bruce into a "Dark Knight", Jeremiah believes he and Bruce are destined to rise from the ashes of Gotham together.
As of Day 96 into No Man’s Land, Jeremiah’s insanity seems to have gotten worse as he is seen arguing with himself and laughing. However, he was able to compose himself when Ecco arrived. He has developed a violent streak as he grabbed Ecco by the throat but then switched to a more cunning persona ( a manipulation tactic) as he pulls her into a dance while she updates him. He values Ecco’s loyalty as he appears to look upset when he thinks Ecco is the one who stabs him, and somewhat relaxes when he realizes it is Selina. At the same time, he doesn’t seem to want her to care about him too much as he becomes annoyed when the bullet in her head is making her sentimental, and orders her to shake her head to get rid of those feelings.
When Barbara stabbed Ecco, Jeremiah was seemingly unaffected, though he stared at her for a few seconds and seemed to slightly hesitate before killing her, casting his eyes downwards to check how injured she is. Since having his mind warped by the gas, he no longer seemed to care about Ecco as a person. He did appear to have an appreciation for her when he called her his “dear sweet Ecco” and said there would never be one like her. It is unknown if he really meant what he said to Ecco, but due to how insane and evil he had become, he appeared to have easily detached himself away from her after killing her. This is reinforced when he later states, "I suppose there are other fish in the sea."
The one constant was his obsession with Bruce as he chose to remain catatonic and in Arkham after Bruce left Gotham, letting inmates harass him without making a move against them. After breaking out of Arkham, he later confesses to Jim about this, saying that Bruce was "the one, the only thing he'd ever loved."
Originally, Jeremiah was identical to his brother. In his first appearance, he had slightly darker hair due to him being more aged (as Jerome had been dead for a whole year before being reanimated). He wore glasses and dressed usually in a red suit and green collared shirt with a purple tie, and occasionally, a blue overcoat.
After his exposure to the insanity gas, Jeremiah's skin turned extremely pale, even paler than his brother's. In addition, his lips became bright red and his eyes piercing green, though he initially hid these changes with makeup and colored contact lenses. As Jeremiah removes both his glasses and (presumably) his contact lenses after revealing himself to Bruce (since his eyes are shown to change from brown to green in the next shot, and subsequently remain green), it appears the gas may have inadvertently improved his vision to the point that he no longer needs glasses. However, he does briefly wear dark sunglasses when he confronts Harvey Bullock outside the GCPD.
After establishing his villainous identity in season 4, he dyes his hair a very dark green and wears a blue-purple suit with a yellow tie, covered with a plaid trench coat and red leather gloves; he later trades the tie with a dark green tie, though he retains the gloves. Occasionally he is also seen wearing a wide-brimmed black hat.
In season 5, Jeremiah wears a black and white coat with a red tie and white hat, he also dyes his hair a lighter shade of turquoise. Later on, he wears a glittered indigo suit with an orange flower in his front pocket, pinstriped trousers, purple gloves, and a whine colored shirt and tie.
After his fall in the acid vat inside the Ace Chemicals during his fight with Bruce, Jeremiah was left extremely burned and scarred, wrapped in bandages, his chin has seemingly grown longer presumably from swelling. His face has changed a lot due to age and his fall into the chemicals, which left him wrinkled and scared on both sides of his face. He now only has a few long strands of green hair. After he escapes Arkham, he puts on a purple shirt and an orange tie. He wears a green tailsuit and pants and a purple overcoat on top. He also wears clown-like leather gloves that are yellow and have red lines along the knuckles.
- "Jim, as an engineer, you expect systems to fail. So, you build in redundancies. And I am a very good engineer."
- —Jeremiah Valeska to Jim Gordon[src]
- Genius-level intellect: Jeremiah is highly intelligent. Since he was a child, he used to draw mazes, and when he grew up, after having the best grades at school, he built one in his house, which he built underneath the woods. Furthermore, he is extremely manipulative as he was able to keep anyone from discovering his insanity for years, even after it was brought to the forefront by Jerome's gas, and he was able to convince everyone that he was Jerome in the tapes he sent to Jerome's followers and the GCPD. Jeremiah also claims to be "vastly more intelligent" than Jerome was. He is a brilliant engineer, designing advanced generators capable of powering Gotham that could double as powerful explosive devices.
- Master engineer: After graduating school, Jeremiah used his construction skills of labyrinths in order to build a secretive hideout for himself in order to defend himself from Jerome, which took him six years of construction.
- Master tactician: Using his vast intelligence, Jeremiah also filled his secret hideout with security cameras in order to be ready for his twisted brother's arrival, whilst also utilizing the right tactics in order to trap and escape Jerome. He was able to formulate a plan to deceive the majority of Gotham City, especially Bruce Wayne and Selina Kyle into believing he was dead whilst also forcing him and Bruce to bond. Even after his Ace Chemicals plan failed, his secondary goal of poisoning Gotham City's rivers and stopping reunification with the mainland succeeded.
- Evasion: Jeremiah has shown to be skilled in evading people, as he was able to evade Jerome for years.
- Impersonation/Acting: Jeremiah was able to impersonate his brother Jerome in multiple video recordings, making him a very talented actor, even capable of fooling the whole GCPD and the Cult of Jerome with his disguise. Later Jeremiah was able to pretend he was actually killed by Selina Kyle as well as being comatose, enduring constant pain and harassment.
- Make-up artist: Jeremiah is a skilled make-up artist. After his skin was bleached white, Jeremiah was able to use make-up to hide his transformation from the public for weeks. He was even capable of taking on the appearance of his brother Jerome by the use of prosthetic make-up for the scars.
- Voice alteration: Jeremiah was able to change his voice to make himself sound like someone else. It was shown that he can convincingly imitate the voice of his brother Jerome, a very difficult task, since Jerome got his striking voice because he got stabbed in the throat before his first death, disfiguring his vocal cords permanently after his resurrection.
- Skilled leader: Before his transformation, Jeremiah was shown to be timid and hesitant around other people, probably due to his long period of social isolation. However, after his transformation by the gas, he became much more confident and charismatic, enabling him to quickly take leadership over the Cult of Jerome and make alliances with Ra's al Ghul and Scarecrow. It's revealed that, in Season 5, he formed his own cult known as the Church of Jeremiah Valeska.
- "Me, if I wanna kill you, I'll just do it. I'll shoot you in the head. Simply and sanely."
- —Jeremiah Valeska to Bruce Wayne[src]
- Expert marksman: Jeremiah has proficiency with guns and other firearms. He was able to shoot and kill one of Jerome's followers without looking at the man behind him using his hidden sleeve gun. He also accurately killed Jongleur with an RPG and paralyzed Selina Kyle by severing her spinal cord with a point-blank shot from his pistol.
- Stealth: Jeremiah has been known to surprise his victims by sneaking up on them from behind, such as when he got the drop on Alfred, forcing his arms to the side and injecting him with Sleep Serum, and when he snuck up on former Demon's Head Barbara Kean, who pushed her into Ecco who then held a knife to her throat.
- Skilled hand-to-hand combatant: Jeremiah has some skill in hand-to-hand combat. This is seen when he managed to pin Tabitha to the ground after stabbing her with her own karambit knife, though he had also taken her by surprise at the time. He was also able to hold his own in a fight with Bruce Wayne.
- Expert knife-wielder: Jeremiah is capable of using a knife. This is seen when he attacked Bruce with a straight razor and when he used Tabitha’s knife against her and almost killed her with it. He proficiently wielded a switchblade during his confrontation with Bruce.
- High pain tolerance/Indomitable will: Jeremiah has a high tolerance for pain, as he showed no signs of pain when Alfred was punching him in the face repeatedly. He later showed only slight signs of pain when shot by Oswald Cobblepot with a machine gun. As he descended more into insanity, it would appear Jeremiah's tolerance has increased as he was able to tolerate Selina Kyle's repeated stabs on a vital part of his body and survive. 10 years after his transformation, Jeremiah has still maintained his amazingly high tolerance, able to get stabbed by Edward Nygma and act comatose whilst only laughing when Batman's ballistic implement pierced his hand.
- Arrogance: Jeremiah believed that he had captured Jerome and could keep him imprisoned. When Jim and Bullock attempted to put him in protective custody, Jeremiah firmly believed he had defeated Jerome. Only for Jerome to outmaneuver him by leading his allies to Jeremiah's location, hypnotizing his bodyguard, and revealing that he memorized the labyrinths that Jeremiah designed as a child. Jeremiah also arrogantly believed that his bomb had killed Jim Gordon, even though he had no proof that he had perished. After his plan to turn Gotham City to ruins succeeded, his sense of ego and hubris grew and Jeremiah gradually became more unhinged after the Cataclysm. He also puts his own life at risk to make his death seem real to Selina, refusing to wear armor that Ecco had prepared for him.
- Mental Instability: More noticeable in the ten-year time jump, after Bruce struck Jeremiah’s hand with a batarang, all he did was point and laugh ecstatically so Bruce could knock him out with another batarang.
- Ecco: Jeremiah seemed to care about Ecco to the point that it would override his instinct for self-preservation when he feared she could be harmed by the Legion of Horribles and refused to leave without her. When he saw her, he ran to her without even suspecting she could be mind controlled, and tried to get through to her to the point where she almost brought him to Jerome. His relief at seeing her could also be that he feels most safe with her around since she could be considered his bodyguard too. This would cause him to be at ease despite being warned of her condition. While he no longer seems to care about her that way after being driven insane by the gas, she can still be considered a weakness as he would never suspect her turning on him, so his guard would be dropped around her. This made it easy for Selina, wearing Ecco's mask and robe, to sneak up on him and stab him. Ten years later, Jeremiah would (in his mind) be forced to kill Ecco after she was wounded by Barbara. He noted there are other fish in the sea, showing that he had gained the confidence to feel that he could now easily replace her.
- Bruce Wayne: Despite having only known Bruce for a short time period, he willingly went to face Jerome against his self-preservation after Bruce's speech about standing up to terror. He was moved and felt enough of a connection to trust Bruce that he decided to go, despite knowing that Jerome was planning on killing him. Jeremiah had also opened the package in his bunker from Wayne Enterprises. The only person in Wayne Enterprises who knew Jeremiah's location (besides Lucius Fox) was Bruce, showing that he thought Bruce had sent him the gift on behalf of Wayne Enterprises. He smiled briefly in response and did not hesitate to open it. Bruce could still be considered a current weakness since Jeremiah refuses to kill him despite Bruce continuing to fight against him and ruin his plans.
- Guns/Firearms: He uses different firearms, primarily handguns, which he appears relatively proficient with. He used a small derringer pistol that retracts from his sleeve to kill a Jerome follower. Jeremiah also used a rocket launcher to destroy Jongleur during his confrontation with Penguin and the Sirens.
- Knives: Jeremiah has used different types of knives. He used a spring-assisted knife given to him by Jerome to try to kill him and make him given to his killer instincts. He used a straight razor taken from Jerome's corpse to attack Bruce and later used another one to kill Sykes. He used Tabitha's karambit knife against her and almost killed her with it. He used a switchblade during his confrontation with Bruce Wayne.
- Bombs/Explosives: Valeska used a wide variety of explosive devices, particularly the specialized generators he had designed and built with the help of Wayne Enterprises. He modified them to serve as bombs; just one was easily capable of leveling a skyscraper. Being a brilliant engineer, he designed highly sophisticated and efficient detonation systems for his explosives as well.
- Jack-in-the-box: Jeremiah kept the jack-in-the-box that sprayed him with Jerome's laughing gas and later used it to traumatize Bruce Wayne while trying to prove to him that one bad day is all it takes to reduce the sanest man alive to lunacy.
- Jeremiah claimed that the gas had no effect on him besides changing his appearance, implying that Jeremiah had always been insane as Jerome mentioned.
- It is possible that Jeremiah's stories about Jerome being insane as a child are fictional and purely a ploy to get sympathy from those around him. This is evident from Jerome's first encounter with Jeremiah, in which Jerome gets emotional when recalling the events of his past whereas Jeremiah is only concerned with running away from Jerome and getting to safety. Jeremiah has also been shown to be self-centered and cowardly which is shown both before and after his transformation.
- This is very in-keeping with most other adaptations of the Joker, who mostly changes details about his own past and sometimes tries to invoke a tragic backstory to gain sympathy (such as when he informed Harley Quinn that he had an abusive childhood in order to manipulate her emotionally).
- Although both Jeremiah and his brother mirror traits exclusive to the Joker, Jeremiah himself is never seen to take on the Joker alias in the show. This was due to licensing issues with the character. The producers of the show describe the character as an "ideology" as opposed to an individual.
- The idea of the Joker as an ideology is heavily emphasized in the show, mostly through Jerome.
- The legacy of Jerome was later reformed by Jeremiah to better suit his personal goals, as Jeremiah wanted to succeed where Jerome failed.
- The idea of the Joker as an ideology is heavily emphasized in the show, mostly through Jerome.
- In "The Beginning", Jeremiah lists off possible aliases starting with "J", including Jack, John, and Joseph (all of which are aliases the Joker has gone by in other media). Alternatively, this could be foreshadowing the Joker alias, which also begins with the letter "J".
- Jeremiah's line after killing Ecco alludes to Harley Quinn, the iconic assistant of the Joker and the character whom Ecco is based on.
- In contrast to his debut in Season 4, Jeremiah is far more unhinged in Season 5. According to Cameron Monaghan, this is because of Jeremiah's newfound ego and hubris after his plan succeeded in Season 4. This resulted in him becoming more arrogant and flamboyant, with the denizens of Gotham City viewing him as a boogeyman figure. Monaghan stated that "J's" final scene in Season 5 is "vile, vicious, nightmare-fuel horror" and that it sums up what he loves about the character. 
- The name "Valeska" may possibly be a reference to the "Valestra gang", a gang in which the man who would go on to become the Joker was associated with, from the film Batman: Mask of the Phantasm.
- Jeremiah falling into the vat of acid in his showdown with Bruce mirrors the Joker's semi-canonical origin from Detective Comics #168.
- Jeremiah became one of the two main antagonists for the final arc of Season 4, sharing the spotlight with Ra's Al Ghul in the season's final episode.
- On various occasions, Gotham writer Tze Chun has been known to informally refer to Cameron Monaghan's characters individually as "This Joker" on his Twitter feed. As of January 2019, he has done this with both Jerome and Jeremiah respectively.
- Actress Francesca Root-Dodson was so startled by Jeremiah's final transformation that she didn't recognize him under the makeup.
- Jeremiah is referred to as "Mr. J" in some promotional material for season 5, which is one of the Joker's most notable aliases, usually referred to by Harley Quinn.
- Jeremiah bears uncanny similarities to the Joker from telltale games, with both having an obsession with Bruce Wayne as opposed to Batman. In addition, both were friends with Bruce prior to becoming villains.
- The Joker made his first appearance in Batman #1 (April 25, 1940). He is credited as having been created by Jerry Robinson, Bob Kane, and Bill Finger.
- Jeremiah Valeska in Season 4 is heavily based on the original Joker from the Golden Age of Comic Books and the Joker from Frank Miller's 1986 Batman: The Dark Knight Returns storyline, where the character was portrayed as more cold and calculating than humorous.
- Like the original Golden Age Joker, Jeremiah Valeska's hair appears in a very dark green tone, almost seeming black in certain light conditions.
- Jeremiah's outfit with the purple hat and coat is an allusion to clothes the Joker wore in the comics on multiple occasions, most famous in Batman: The Killing Joke, as well as the 1989 live-action movie Batman.
- When Jeremiah is undergoing his villainous transformation, he clutches his head in a way that mirrors the famous panel of The Joker going insane in Batman: The Killing Joke.
- Xander's assumed surname could be a reference to the wild and unpredictable nature of the Joker. It could specifically be a reference to an episode of Batman: The Animated Series called "Joker's Wilde".
- The surname is actually a German word which translates to several meanings such as 'savage', 'maniac' and 'madman'.
- His role as an engineer is likely a reference to the Joker’s backstory in The Killing Joke where it is mentioned that he was an engineer at the Ace Chemicals plant before becoming a stand-up comedian.
- Jeremiah and Jerome share the same facial features apart from environmental changes.
- Jerome being dead for a whole year without aging makes Jeremiah physically older than him, which would explain Jeremiah's slightly darker hair.
- His fake death is similar to that of his brother Jerome's first death at the hands of Theo Galavan, who was also stabbed.
- Unlike his brother Jerome, Jeremiah's first debut into crime completely fooled Gordon and the entire GCPD, who did not even consider him a suspect. His facade could arguably have remained undiscovered for some time had he not revealed himself as the culprit to both Bruce Wayne and Jim Gordon.
Behind the scenes
- Even though Jeremiah is the series' exploration of the Joker's origins, he was never referred to as "The Joker" as Cameron Monaghan confirmed on his Twitter account due to Warner Bros. wanting to use the name "Joker" for future projects. Cameron also confirmed Jeremiah cannot have bright green hair.
- The promo for Jeremiah's first appearance "A Dark Knight: Mandatory Brunch Meeting" teased the Joker's arrival with the question "Who Is The Joker?".
- The name Jeremiah is possibly used to invoke the similarity with the prophet Jeremiah from Christian, Jewish and Islamic theology. The prophet frequently prophesied the coming doom of the cities of Judah and Jerusalem due to their sins. Jeremiah Valeska plays a similar role especially after his meeting with Ra's Al Ghul, wherein he predicts Gotham city's eventual fall, although unlike the prophet, Valeska is a direct cause of that coming chaos. Valeska's role before his transformation is also largely reluctant and similarly good-natured as the prophet, wanting to save the residents of the city under threat rather than punish them.
- There is a saint Jerome partly known in Christian theology for examining the lives and words of Biblical prophets and making detailed commentaries about them. In a vaguely similar fashion, Jerome Valeska also briefly examines and reflects upon the previous work of his brother Jeremiah as well as providing his own insights on their meaning.
- Jeremiah's entire alias of Xander Wilde may, in fact, be a reference to the medieval Minnesänger Der Wilde Alexander whose poems often shed negative light upon the decadence of his time.
- ↑ https://www.youtube.com/watch?v=iwd13B24cXY
- ↑ https://youtu.be/CKqLShAoWIw
- ↑ Lilien, Steven & Wynbrandt, Bryan (writer) & Vrvilo, Maja (director) (April 5, 2018) "A Dark Knight: Mandatory Brunch Meeting" Gotham. Season 4. Episode 17.
- ↑ Cannon, Danny (writer) & Copus, Nick (director) (April 12, 2018) "A Dark Knight: That's Entertainment" Gotham. Season 4. Episode 18.
- ↑ Huston, Charlie (writer) & Milto, Louis Shaw (director) (May 3, 2018) "A Dark Knight: That Old Corpse" Gotham. Season 4. Episode 20.
- ↑ Chun, Tze (writer) & Bailey, Rob (director) (May 10, 2018) "A Dark Knight: One Bad Day" Gotham. Season 4. Episode 21.
- ↑ Stephens, John & Boston, Seth (writer) & Hope, Nathan (director) (May 17, 2018) "A Dark Knight: No Man's Land" Gotham. Season 4. Episode 22.
- ↑ Fiveash, Chad & Stoteraux, James (writer) & Hope, Nathan (director) (January 24, 2019) "Ruin" Gotham. Season 5. Episode 4.
- ↑ Sosa, Iturri (writer) & Tonderai, Mark (director) (January 31, 2019) "Pena Dura" Gotham. Season 5. Episode 5.
- ↑ Sosa, Iturri (writer) & Tonderai, Mark (director) (January 31, 2019) "Pena Dura" Gotham. Season 5. Episode 5.
- ↑ (writer) & (director) (April 25, 2019) "The Beginning..." Gotham. Season 5. Episode 11.
- ↑ https://www.gamespot.com/articles/gothams-next-joker-evolution-is-actually-a-nightma/1100-6465237/
- ↑ https://comicbook.com/dc/2018/11/09/gotham-cameron-monaghan-jeremiah-final-appearance/
- ↑ 
- ↑ https://mobile.twitter.com/thetzechun/status/982035211910168576
- ↑ https://mobile.twitter.com/thetzechun/status/1077327315577786370
- ↑ https://mobile.twitter.com/thetzechun/status/1076711476365328384
- ↑ https://comicbook.com/dc/2019/03/06/gotham-jeremiah-joker-evolution-reaction-francesca-root-dodson/
- ↑ https://twitter.com/cameronmonaghan/status/995422386437570560