Characters

The following characters have been shown or mentioned in the show

Arkham Asylum Employees
Doctor Jeremiah Arkham - The head doctor of the asylum. Very devoted to his wife. Dr. Quinzel seems very disgruntled with his methods according to "My Funny Valentine" and "Find Patient 4479". Starting in the episode "Car Trouble", Jeremy is a hostage to the Joker, who breaks out of his cell.

Intern Harleen Quinzel - An ambitious young shrink who is the object of Joker's affections, shown in "A Apple A Day". In "Shootgun Wedding" it's heavily implied that she has started to loose her sanity. In the comics, she becomes the villian Harley Quinn due to the Joker's influence.

Nurse Pearl - According to "Artistic Merit", she may be a close friend to Harleen and her future husband, Guy Kopski. She is Joker's driver starting in "Road Trip".

Lyle Bolton - Chief security officer. Joker took an immediate dislike to him in the episode "A Dream Come True" and gets back later by making him perform humiliating tasks in "Road Trip". According to a radio station in the episode "Get Me To The Church On Time", the GCPD have found Lyle.

Doctor Hugo Strange - When Arkham had to make cut-backs, Harleen was let go for a short amount of time. Hugo Strange was set as Joker's new doctor. During a psychotherapy test, the Joker claimed to have had a relation with Hugo's wife, leading the hot-tempered Strange to physically attack the Joker and possibly lose his job. In the comics, he's one of Batman's worst enemies.

Dr. Cavendish - Although not a regular character on the show, Dr. Cavendish does not agree with how Dr. Arkham handles the hospital.

Inmates
The Joker (Patient #4479) - With no memory, or a refusal of remembering, his past, the Joker is considered to be faking insanity. In "The Dark Knight", Joker terrorized Gotham. He claims to never have a plan, but the whole thing was part of his plan. After his apprehension by Batman, the Joker was sent to a re-opened Arkham. Interning psychiatrist Harleen Quinzell is his primary doctor. He is known for breaking out of his cell many times. Currently, he is on a "road trip" with Nurse Pearl, Doctor Arkham, and Officer Bolton as his hostages.

(Former) Doctor Jonathan Crane (AKA Scarecrow) - In "Batman Begins", Johnathan was a doctor at Arkham Asylum, but used his specially-formulated "fear gas" on his patients in unauthorized "experiments". He also worked with Ra's Al Ghul throughout the beginning of his career as Scarecrow. Once Rachael Dawes shot him in the face with a tazer, he disappeared for a long time, leading people to believe he had died. In the antimated film "Batman: Gotham Knight", a large mutant man attacks a church. When Batman follows his trail, he learns that Scarecrow is behind the attack in some way. After fighting Killer Croc, a former patient who is now mutated into a mindless monster, Batman finds Scarecrow in the sewers with followers. In "The Dark Knight", we learn he has been selling his "drug" to criminals. Unfortunately, the drug has an extremely long half-life in the human body. That, combined with the fact that his fear toxin produces a waking nightmare, has made drug-distributing mobsters very unhappy with Scarecrow due to a lack of "repeat business". We find out in The Joker Blogs that he is now an Arkham prisoner. He and Joker do not get along. In fact, they are at each others throats. We also find out that he and Harleen have had a "thing" before. Scarecrow also warns Harleen that the Joker is not faking.

Carmine Falcone (Mentioned only) - Carmine is known as a former crime boss who was the first victim of the Batman's crusade. He was the cell mate of Joe Chill, the murderer of Bruce Wayne's parents. When Batman apprehended him, Doctor Johnathan Crane was appointed to evaluate him for insanity. Crane made Falcone apparently insane by exposing him to his fear toxin, sending Falcone to Arkham Asylum. His current status is unknown, but it is known that he and Joker have met each other and Joker considers him a "friend" of some sort.

GCPD
Officer Harvey Bullock - A GCPD officer who questioned the Joker after he broke out of the prison and went on a "road trip" with three Arkham employees as his hostages. According to Bullock, the Joker killed his partner. Bullock is an aggressive officer. In the comics, he is Comissioner Gordan's right-hand officer.

Officer James (Jim) Corrigan - Harvey Bullock's partner, who was present at the time Bullock questioned the Joker.

Others
Guy Kopski - Harleen Quinzel's (former) fiance', whom Joker killed in "Shotgun Wedding".

Garet Kopski - Brother to Guy Kopski, whome the Joker killed by electricuting him in "Killing Kopski"

Lisa Arkham - Jeremiah Arkham's wife, whose picture the Joker pilfered from the doctor's desk on several occasions. She was later attacked and terrorized, along with her husband, by the Joker in their own home. (The Joker has an apparent penchant for beautiful women, especially as victims.)

Theodor - Homeless man found in the Narrows. The Joker offered him a "job" while on his road trip. Theo complained about the events that led to his homelessness, including the destruction of his car by a "weird, armored motorcycle". He also has a severe lack of training or skill with firearms. His precense in the series further blurs the the shows already vague line between comedy and horror.

Batman - Only mentioned before, makes his first appearance on the show in episode 17, "Shotgun Wedding". When Bruce Wayne was only about 8 years old, Joe Chill murdered both is his parents in front of him. This followed him through his adolesance and in his adult hood. He left Gotham for about seven years, traveling the world, looking for a way to deal with his pain and wanting to find a way to show Gotham true justice. After meeting Ra's Al Ghul, going by "Henry Dicard", Bruce began training to become part of the League of Assassins. Once he learned their full intentions and refused to murder and, after a fight with the League, left and went back home. Once home he started, slowly, getting ready to become the vigilante known as Batman. As Batman, he took out Falcone and his men and made a partnership with James Gordon, secretly. Eventually, Ra's came to Gotham, wanting to destroy it, Batman eventually stopped him, possibly killing him in the end. After that (In Batman: Gotham Knight), he met with officers Crispus Alan and Ana Ramirez, had his first battles with Maroni and his men, fought Killer Croc, found the supposidly dead Johnathan Crane, and took down a notorious assassin named Deadshot! Eventually, Batman did take down Scarecrow, finally tossing him in Arkham, along with stopping some "Batman Copycats". Soon after that, he began tracking down the Joker with James Gordon and the new DA, Harvey Dent. After Joker had kidnapped both Rachel Daws and Harvey, Rachel died and Harvey was physically scarred on his face, making him insane. When Batman had finally taken down The Joker, he went after the homicidal Harvey Dent, now going by "Harvey/Two-Face". Before Harvey could kill anyone, Batman attacked him, knocking him off the side of the building, seemingly killing him. When the dead has been done, Batman tells Gordon that Harvey didn't kill those people. In The Joker Blogs, Batman fights Joker in the Catholac church, telling Joker that he's wondering if he should have kept him alive in the first place. He's then shot in the side by Harleen, letting Joker's attention leave him and let him leave. His current whereabouts are unknown.

Jack Ryder - Taped the wedding, the death of Guy Kopski, and the battle between Batman and Joker in the episode "Shotgun Wedding". In the comics, Jack goes by "The Creeper".

Dr. Thomas (Tommy) Elliot - Came late to the wedding of Guy Kopski and Harleen Quinzell in the episode "Shotgun Wedding". Apparently, he has some sort of history with Hugo Strange, leading them to not like each other. In the comics, Thomas is Bruce Wayne's best friend since childhood. He becomes Hush to take revenge on Bruce because Bruce's father saved Thomas's mother, after a planned car crash, which killed Thomas's father. This lead Thomas to have to wait for his enharitence until his mother died of cancer.