- "Don't compare me to that short sighted psychopath. He just wanted to destroy things. Me...I'm a builder. I'm gonna create a new Gotham in my image, but every artist needs a blank canvas so all of this has to go."
- —Jeremiah to Harvey Bullock[src]
Jeremiah Valeska is a mentally deranged and dangerous terrorist, criminal and murderer. He is also the more intelligent and more dangerous identical twin brother of the anarchistic cult leader Jerome Valeska.
As a child, Jeremiah suffered years of abuse at the hands of his psychopathic brother, who even burnt Jeremiah's bed while Jeremiah himself was in it. In a desperate attempt to defend Jeremiah from his monstrous brother, his uncle took him away from Haly's Circus, in which his mother Lila worked, and proceeded to take him to St. Ignatius. Following this Jeremiah changed his name and started calling himself Xander Wilde. After finishing school, Jeremiah had become a highly intelligent engineer, and since a young age, he used to construct labyrinths and built a hideout of his own to protect himself from his brother, which took almost six years of construction. In addition to the hideout which he filled with security cameras, rooms of work and more, he met a young woman named Ecco who started to work for him as a proxy and assistant. Jeremiah would later reunite with his brother, who after a rampage to find his twin, found him in his hideout.
Right after witnessing his brother's death, Jeremiah received a gift which was sent to him by Jerome, which is revealed to be a "special" gas created just for him. Upon inhaling it, his face became pale white and a wide red grin formed from ear to ear, turning Jeremiah insane, ultimately becoming The Joker.
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 afterwards, Jeremiah took on the alias of "Xander Wilde". He himself would later explain that he did this since he wanted to make it more difficult for Jerome to track him down, but Jerome on the other hand stated that he got adopted by rich people, therfore explaining his changed name.
He would then study at school and become 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, 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 him and Jerome, he tells them that once Jerome tried to kill him, so he ran away and changed his name to Xander Wilde. They then find out that he‘s holding Jerome captive, so they immediately order Jeremiah to let him go but he refuses to do so. After finding out that the Legion of Horribles is inside the building, and that they hypnotized Ecco, Jeremiah takes Jim and Harvey into the halls of his house, which were built as a maze that he’s the only one he can get out of. The three find Ecco there but, since she was hypnotized by Tetch, she gets into a fight with them, Ecco easily wins and takes Jeremiah to Jerome, but she’s eventually 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 a police officer 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.
Driven InsaneAfter Jerome's death, Jeremiah discovered a gift in his secret office and opened it. The gift is revealed to be a jack in the box in the form of a disfigured clown head that sprays Jeremiah with a special mixture of the laughing venom created by Jerome. The gas then eventually drives Jeremiah completely insane as Jerome's voice speaks to him in a recording coming out of the gift box, encouraging Jeremiah to be Jerome's successor and his ultimate revenge. Even though Jeremiah tried to fight the venom, it ultimately turned him into a complete maniac with white skin and red lips, ultimately becoming The Joker. However, Jeremiah claimed that other than the cosmetic changes, the gas did nothing to his sanity: this indicates that Jerome was telling the truth about Jeremiah's mental state, and that he indeed shares his brother’s psychosis.
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 he 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, Jeremiah reveals his true colors to Bruce by confessing that the whole event was just an act and Jeremiah was insane the whole time. After a thug proclaims proudly "Jerome's victorious" Jeremiah murders him in cold blood due to him believing that he was the victorious one and not his brother since he was dead. He then revealed his plans for Gotham as he pulled out the diary and stated he was going to complete his brother’s wishes in a sane matter. Bruce disregarded his plan by saying its complete madness and then he states that he wouldnt go as extreme and brutal as his brother but rather get things done straight to the point he said "Jerome wanted to slather you in honey and have you eaten alive by corpse beetles. Now that's mad. Me if I wanted to kill you I'd just do it. I'll shoot you in the head. Simply and sanely". He then reveals to Bruce that the generators he invested his money in were going to be used as bombs rather than electricity resource. Back at Jermiah's residence the bunker's generator starts a timer for an explosion, but luckily Jim finds a secret buzzer underneath the table and unlocks the door and escapes the bunker. as the bunker explodes. Jeremiah presumes Jim has died and passes on that information the Bruce, where Bruce angrily vows that he will stop Jeremiah.
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 powerful 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
Confronting Bullock, Jeremiah announces he has bombs hidden around Gotham City and states if Bullock were to do any harm to Jeremiah, the explosives will trigger. Jeremiah gives Bullock six hours to evacuate the city and destroys the Gotham Clock Tower to show he is telling the truth. Later, when Bruce met with Bullock, Jeremiah calls him and tells him the address Alfred, who Jeremiah had kidnapped, is at and warns Bruce not to tell the police as Jeremiah knows where Bruce is. As Jeremiah enters his safehouse, he findsThe Penguin, Barbara Kean, Tabitha Galavan, and Butch Gilzean waiting for him with one of Jeremiah's henchmen hostage. They demand an additional hour to evacuate the city and $50 million. Jeremiah calls the mayor and then pulls out a bazooka and kills the henchman. Jeremiah then tells them he has changed his mind and will detonate the bombs when he's a safe distance away. Jeremiah orders them to be killed and escapes. Later when he's in another bunker, Jeremiah prepares to detonate the bombs however finds out that Gordon is still alive, much to his anger and frustration. Jeremiah triggers the explosives however fails as Bullock had disabled him on time.
The followers get angry at Jeremiah and he ultimately decides to seal them inside a chamber and set them on fire. Later, Jeremiah plans to start over when he is met by Ra's al Ghul who explains its not about Gotham; it's about Bruce. Later when Bruce and Selina are talking, Jeremiah unexpectedly shows up and shoots Selina in the stomach. Alfred comes in and takes down Jeremiah with Bruce comforting Selina.
Aligned with Ra's al ghul
After being arrested, Jeremiah was held at the GCPD. Talking with Gordon, Jeremiah claims he has planted other bombs around the city. A few moments later, a bomb goes off, killing the mayor. A major has Bruce Wayne meet with Jeremiah, attempting to get the location of the other bombs. Jeremiah only taunts him about Selina and Bruce gets frustrated and orders him to tell him where he hid the bombs.
Jeremiah finally reveals to Bruce he is working with Ra's al Ghul. Bruce and Jeremiah are then taken to Ra's. Ra's and Jeremiah tell Bruce they'll create a legacy when Barbara Kean, Tabitha Galavan, Penguin, and Alfred arrive and Barbara and Bruce kill Ra's who tells Bruce to become Gotham's dark knight. Suddenly, the bombs had Ra's and Jeremiah had planted go off and destroy the bridges connecting Gotham. Jeremiah begins to smile and escapes off screen.
His current location is unknown.
Though he appeared to be more stable then his brother, calling him after his transformation a “Short-sighted psychopath, he 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 was threatening to kill him, though he later admitted to Jerome that it didn't happen exactly as he had described it. He also tried to deceive Jim Gordon and Harvey Bullock that Jerome could not find him, even though he had captured Jerome at this point. He was overconfident, bordering on arrogance, on being able to keep his brother trapped, something that led to Jeremiah escaping him. He was also willing to let people die if it meant he could avoid Jerome, showing that he was selfish to a degree.
After being exposed to Jerome's altered laughing toxin, Jeremiah was 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, indicating that he was truly psychopathic all along. Since this event, he has shown traits quite similar to his brother, showing ruthlessness as he executed one of Jerome's followers in cold blood for pronouncing Jerome to be victorious. He also showed arrogance, as he believed he was complete Jerome's plans in a "sane" manner. Jeremiah has still shown himself to be highly deceptive, as he was able to act as Jerome on video tapes of his "will", only dropping the act to illustrate his new sinister personality. Jeremiah has also shown to be calm at all times, even when he is furious and speaking in a monotonous tone for the most part.
However, despite appearing calmer than Jerome, he does have the same explosive temper, screaming at his followers to prevent them attacking him, which led to him burning them all to death, showing the same disregard for others that his brother showed. He also shows a denial about his insanity, as he claims he is not insane several times. Despite being in denial about his insanity, he seemed to realize he is insane and has forgiven his brother, likely because he realizes that he shouldn't have abandoned Jerome and believes it was his mother's fault Jerome was insane.
Originally, Jeremiah was identical to his brother, the only exeption being his slightly darker hair. He wore glasses and dressed usually in an orange suit and blue collared shirt, and occasionally, a blue coat. After his exposure to the insanity gas, Jeremiah's skin was turned extremely pale. In addition, his lips became bright red and his eyes piercing green. He later dyed his hair a very dark green and wore a purple and black suit.
- High-level intellect: Jeremiah is shown to be 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.
- High pain tolerance/Indomitable will: Jeremiah has shown to have 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.
- 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.
- Evasion: Jeremiah has shown to be skilled in evading people, as he was able to evade Jerome for years.
- 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.
- Impersonation/Acting: He 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.
- Make-up artist: Jeremiah is shown to be a skilled make-up artist on many occasions. 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 Marksman: Jeremiah has shown profiency 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.
- Skilled Knife Wielder: Jeremiah is skilled at using a knife. This is seen one he attacked Bruce with a straight razor and when he used Tabatha’s karmbit knife against her and almost killed her with it.
- Hand to Hand Combatant: Jerimah has shown 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..
- 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.
- Jerome: Jeremiah's greatest weakness is Jerome, his own twin brother. Since a young age Jeremiah suffered from Jerome's twisted and sadistic personality this led to Jeremiah suffering at the hands of Jerome who tormented him violently and sadistically, at one point during this period Jerome even set fire to Jeremiah's bed while he was still in it. Jerome also wished to have Jeremiah carry on his legacy by spraying him with a “special gas” that could drive him insane. However, the gas merely changed Jeremiah’s face and did not have any effect on his true deranged mentality.
- Guns/Firearms: He uses different firearms such as handguns and even rocket launchers. He used a small pistol that retracts from his sleeve to kill a Jerome follower.
- 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. He used Tabitha’s karmbit knife against her and almost killed her with it.
- "A Dark Knight: Mandatory Brunch Meeting"
- "A Dark Knight: That's Entertainment"
- "A Dark Knight: That Old Corpse"
- "A Dark Knight: One Bad Day"
- "A Dark Knight: No Man's Land"
- The Joker made his first appearence in Batman #1 (April 25, 1940). The original character was created by Jerry Robinson, Bob Kane, and Bill Finger and first appeared in Batman #1.
- This is the third live-action version of the Joker to appear on television and the sixth live-action version overall(excluding the various actors involved in various commercials involving the Joker such as the recent Snickers ad campaign), with the first being in the 1966 live-action TV series Batman played by Cesar Romero, the second in the 1989 live-action movie played by Jack Nicholson, the third in the 2002 live-action TV series Birds of Prey played by Roger Stoneburner and voiced over by Mark Hamill, the fourth in the 2008 live-action movie The Dark Knight played by Heath Ledger and the fifth being in the 2016 live-action movie Suicide Squad played by Jared Leto.
- Jeremiah Valeska is heavily based on the original Joker from the Golden Age of Comic Books as well as the Joker from Frank Miller's 1986 Batman: The Dark Knight Returns storyline, where the character was potrayed as much more cold and calculating while also lacking damaged face muscles and nerves that make him look like he was smiling all times.
- Like the Joker from Batman: The Animated Series from 1992, 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 in the comics on multiple occasions, most famous in Batman: The Killing Joke and Batman: No Man's Land, as well as the 1989 live-action movie Batman.
- When Jeremiah is going insane, 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".
- Jeremiah and Jerome share the same facial features apart from Jeremiah's hair being dark brown, with Jerome's being red, and Jeremiah wearing glasses.
- It appears that Jeremiah dyes his hair green instead of it being chemically changed, similar to Heath Ledger's Joker.
- It is possible that Jeremiah's stories about Jerome's being a psychopath as a child, are fictional and purely a ploy to get sympathy from those around him.
- It is highly assumed that Jeremiah will be the cause of Ra's al Ghul's vision of The Fall of Gotham in the near future.
- Even though Jeremiah acts as Gotham's version of the Joker, he will never be called "The Joker" as Cameron Monoghan confirmed on his twitter account due to Warner Bros. wanting to use the name "Joker" for future projects. Cameron also confirmed Jeremiah can not have bright green hair.
- Jeremiah stated that being sprayed with Jerome's special laughing gas caused no change in his mentality, indicating that he was insane before he was sprayed, the gas just brought his insanity to the forefront of his mentality. The gas simply changed Jeremiah's facial appearance.
- ↑ https://www.youtube.com/watch?v=iwd13B24cXY
- ↑ 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.
- ↑ https://twitter.com/cameronmonaghan/status/995422386437570560