- Anarky Detective Comics #608 (November 1989) Lonnie Machin, a teenage prodigy who, believing in anarchism, creates improvised gadgets and attempts to subvert government in order to improve society. Initially very young (age 12), his costume was designed to disguise his true age. More recent stories portray him as being in his late-teens. Batman recognizes him as a force for good, but does not support his violent methods. Anarky was later the subject of a spin-off series, Anarky, and trade paperback, Batman: Anarky.
- Bane Batman: Vengeance of Bane #1 (January 1993) An escaped convict from an island prison in South America, Bane has abnormal strength as a result of having had experiments with a derivative of the drug Venom performed on him. He became known as "The Man Who Broke the Bat" when he broke Batman's spinal cord, forcing Bruce Wayne to give up the Batman persona while he recuperated.
- Batzarro Superman #181 (April 2002) A distorted clone of Batman, presumably created through the same process as Bizarro, the failed clone of Superman. At times it seems as though Batzarro is trying to aid Batman, but his mangled dialogue and inexplicable actions make it difficult to be sure.
- Black Mask Batman #386 (August 1985) Roman Sionis, a former business executive who originally hated Bruce Wayne rather than Batman, wears a Black Mask and leads the cult-like False Face Society of henchmen. Black Mask eventually became a mob boss controlling large sections of Gotham's criminal underworld.
- Blockbuster Detective Comics #345 (November 1965) Two brothers took the alias of Blockbuster in turn. The first, Mark Desmond, was a chemist who experimented on himself and gained super strength, but also became a mindless brute. He would eventually die fighting Brimstone, a minion of Darkseid. Mark's older brother, Roland Desmond, was mutated when he was treated with experimental steroids, also gaining massive strength.
Starman #9 (April 1989)
- Calendar Man Detective Comics #259 (September 1958) Julian Day is known for committing crimes that corresponded with significant dates.
- Catman Detective Comics #311 (January 1963) Catman was originally Thomas Blake, a world-famous trapper of jungle cats who turned to crime because he had grown bored with hunting and had squandered most of his fortune. He became a burglar who committed his crimes in a catsuit made out of an ancient African cloth he believed gave him a cat's nine lives.
- Catwoman Batman #1 (Spring 1940) Selina Kyle, starting as a criminal who wore a cat-themed costume and often operated as a burglar, has a love/hate relationship with Batman. For years, she skirted on the edge between villain and antiheroine. However, she has largely reformed in recent years, adopting the role of the guardian of Gotham's crime-infested East End, though she still comes into conflict with Batman on occasion. She has also been known to take revenge upon those who commit crimes against animals, especially large cats.
Detective Comics #40 (June 1940) Basil Karlo, The original Clayface, Basil Karlo, was an actor who was driven mad when he heard of a remake of the classic horror film he had starred in, The Terror. Adopting the persona of the film's villain "Clayface", he became a serial killer targeting the cast and crew. He was eventually stopped by Batman and Robin. Later, Karlo would be imbued with the powers of Clayfaces Preston Payne and Sondra Fuller. Additionally, his body sports crystals similar to quartz that endow him with greater powers. In this form he is known as the "Ultimate Clayface." He is the Clayface who is currently active in crime. Detective Comics #298 (December 1961) Matt Hagen, was a treasure hunter who happened upon a radioactive pool of protoplasm. He submerged himself in it, granting himself powers allowing him to transform into almost any shape. Hagen was ultimately killed during the 12-issue limited series Crisis on Infinite Earths. Detective Comics #478 (July 1978) Preston Payne, suffered from hyperpituitarism and worked at S.T.A.R. Labs to search for a cure. He obtained a sample of the then-living Matt Hagen's blood, and isolated an enzyme which he introduced into his own bloodstream. His flesh began to melt, however, and he built an exoskeleton anti-melting suit to not only preserve himself, but to also prevent him from touching anyone, as he also gained the ability to melt people with a touch. He soon learned that he needed to spread his melting contagion onto others to survive. Outsiders #21 (July 1987) Sondra Fuller, has abilities similar to Matt Hagen, but can also mimic the special power of the being she is mimicking. She met and fell in love with Preston Payne, and the two had a son named Cassius, the fifth Clayface.
- Cluemaster Detective Comics #351 (May 1966) Arthur Brown is a former game show host who turned to a life of crime and left clues at the scene of the crime. He is also the father of The Spoiler (Stephanie Brown).
- Deadshot Batman #59 (June-July 1950) Floyd Lawton is a suicidal assassin who wears a colorful costume in the hopes that someone will shoot him. He is considered the second greatest assassin in the DC Universe, the first being Deathstroke.
- Firefly Detective Comics #184 (June 1952) Garfield Lynns, an orphan who became a pyromaniac and has developed a fireproof suit and flamethrower to further pursue his 'hobby'. He was originally known as a cunning criminal who invented numerous weapons that use light to commit crimes with.
- Harley Quinn Batman: The Animated Series "Joker's Favor" (September 11, 1992) Dr. Harleen Quinzel, a former criminal psychiatrist, fell in love with the Joker and became his most famous accomplice. She is the first enemy of Batman to be introduced outside the comics and go on to receive her own line of comics. She wears the outfit of a traditional harlequin jester. She affectionately refers to the Joker as "Puddin'" and "Mistah' J", and is best friends with Poison Ivy.
- Hugo Strange Detective Comics #36 (February 1940) Strange is an insane psychologist who knows Bruce Wayne's secret identity and lusts to take the identity for himself. He is also a chemical genius who can turn people into large, lumbering, brutal zombie-like creatures that obey his every command.
- Hush Batman #609 (November 2002) A childhood friend of Bruce Wayne's, Thomas "Tommy" Elliot targets both Batman and Bruce Wayne. Although Hush's name originates from a nursery rhyme, Hush lives up to it by using manipulation and guile instead of noisy "signatures".
- The Joker Batman #1 (Spring 1940) The Joker is a homicidal maniac with a clown-like appearance who takes comedic delight in violent crime and challenging Batman. He is generally acknowledged to be Batman's arch-nemesis and worst enemy, gleefully citing the relationship between the two as being Comedy and Tragedy, Chaos and Order, two sides of the same coin. He was responsible for the crippling of Barbara Gordon, the brutal murder of the second Robin (Jason Todd), and the murder of Sarah Essen Gordon (James Gordon's second wife). He often goes by the alias "Joe Kerr", an obvious play on his moniker.
KGBeast Batman #417 (March 1988) Anatoli Knyazev is a ruthless assassin who Batman encounters many times. Later, while KGBeast is on a mission to assassinate Ronald Reagan, Batman catches KGBeast's left wrist in a loop of the bat-rope, but KGBeast cuts off his own hand with an ax in order to escape. He later returns with a cybernetic gun prosthetic attached to his wrist. He is finally killed by the second Tally Man.
- Killer Croc Detective Comics #523 (February 1983) Waylon Jones, a former croc wrestler turned into a criminal deformed by mutation into a humongous humanoid lizard, has low intelligence but great strength, as well as crocodilian abilities, such as a keener sense of smell and the ability to hold his breath underwater for long periods of time.
- Killer Moth Batman #63 (February 1951) Cameron van Cleer/Drury Walker was an anti-Batman who aided criminals just as Batman aids the police, but only for money. He later sells his soul to the demon Neron and transforms into the monster Charaxes. A new human Killer Moth has recently appeared in Batman: Face the Face, but the identity of this version is unknown.
- The Mad Hatter Batman #49 (October-November 1948) Jervis Tetch, formerly a research scientist, is completely smitten with the works of Lewis Carroll. He is an insane neuroscientist and developed hardware that can control the brain and induce hypnotic states, and often uses hats or other headgear for mind control. (There was also, briefly, a second Mad Hatter who liked to commit crimes with hat-related themes, but he has not been seen in two decades, having only one appearance after nearly being killed by the original.)
- Man-Bat Detective Comics #400 (June 1970) Dr. Kirk Langstrom, sometimes an enemy of Batman, is unfortunately cursed to periodically turn into an animalistic humanoid bat. As a scientist, Kirk Langstrom is Batman's ally.
- Maxie Zeus Detective Comics #483 (May 1979) Maximillian "Maxie" Zeus was a former history teacher. He became an insane mob boss with a penchant for Greek mythology. Maxie had a god complex and usually used electrically-based weaponry to emulate the Greek god Zeus.
- Mr. Freeze Batman #121 (February 1959)
as "Mr. Zero"; designation changed in 1960's TV series Dr. Victor Fries was formerly a scientist and is an expert on cryonics. He tried to cryopreserve his stricken wife Nora Fries until a cure was found to her disease. During the process, an accident caused his body to function only below freezing point, requiring him to wear a special self-contained refrigeration suit. He uses similar ice technology for weapons.
- Mr. Zsasz Batman: Shadow of the Bat #1 (June 1992) Victor Zsasz, a more or less "common" serial killer, keeps a tally of his victims by cutting new scars into his body with his trademark carving knife.
- The Penguin Detective Comics #58 (December 1941) Oswald Chesterfield Cobblepot, a short round man with a long pointed nose, fancies himself a gentleman of crime. He usually wears a tuxedo, top hat, and monocle, and carries any variety of umbrellas which have various hidden functions such as vehicles or weapons.
- Poison Ivy Batman #181 (June 1966) Pamela Lillian Isley, a former student of advanced botanical biochemistry, employs plants of all varieties and their derivatives in her crimes. She has the ability to control/manipulate all plant life and is immune to all poisons and toxins. She is often described as fanatical about defending plants from other humans, even being willing to murder for her beliefs. She also has a severe love/hate relationship with Batman. In some instances she claims to love him, in other encounters she functions as an ally, and at other times she is more than willing to kill him.
- Ra's al Ghul Batman #232 (June 1971) Ra's al Ghul ("Demon's Head" in Arabic), is a centuries-old eco-terrorist. He knows Batman's secret identity. He utilizes special pits known as Lazarus Pits which enable him to evade death, and live for centuries. He is the founder of the worldwide League of Assassins, though exactly when is unknown.
- Red Hood Detective Comics #168 (February 1951) An employee looking to steal from the company that employs him adopts the persona of Red Hood. After committing the theft, which Batman thwarts, the Red Hood falls into a vat of chemical waste. He subsequently emerges with bleached white skin, red lips, green hair, and a permanent grin, later calling himself the Joker.
Batman #635 (December 2004) Formerly the second Robin, Jason Todd was killed by the Joker, who beat him half to death and left him in an exploding warehouse. Jason re-emerged years later as the new Red Hood, ironically the Joker's old alias. Notoriously brutal in his run as Robin, he has shown he has no problem with killing criminals.
- The Riddler Detective Comics #140 (October 1948) Edward Nigma is a criminal mastermind who has a strange compulsion to challenge Batman by leaving clues to his crimes in the form of riddles and puzzles. Recently, he has seemingly abandoned his criminal lifestyle and has opted to utilize his skills to turn a profit as a freelance investigator.
- The Scarecrow World's Finest Comics #3 (Fall 1941) Prof. Jonathan Crane, an insane scientist and psychiatrist, specializes in the nature of fear. Dressed symbolically as a scarecrow, he employs special weapons, equipment and techniques designed to use fear to his advantage in his crimes.
- Solomon Grundy All-American Comics #61 (October 1944) Formerly Cyrus Gold, a Gotham City merchant murdered and thrown into Slaughter Swamp, where he was transformed into an undead zombie-like creature. Solomon Grundy was initially an enemy of the Golden Age Green Lantern and the Justice Society, but has both battled and aided various heroes during his multiple resurrections. He has battled Batman on a number of occasions, notably in The Long Halloween and Dark Victory.
- Tweedledum and Tweedledee Detective Comics #74 (April 1943) Dumfrey and Deever Tweed are a pair of rotund cousins, whose similar looks often have them mistaken for identical twins. Fat and lazy, the pair prefer to direct henchmen to carry out crimes, while they retire to a safe haven. The pair often wear costumes modelled on their namesakes from Lewis Carrol's Through the Looking-Glass (and what Alice found there).
- Two-Face Detective Comics #66 (August 1942) Formerly District Attorney Harvey Dent (a friend of Bruce Wayne's). Dent's latent multiple personality disorder fully took hold when half his face was horrifically scarred by Sal Ma
roni. He became obsessed with committing crimes themed around duality and opposites. He makes major decisions by flipping a two-headed coin on which one of the faces is scarred. Over the years, he has reformed at various times, with his face being surgically repaired, only to later fall back into the Two-Face persona.
- The Ventriloquist Detective Comics #583 (February 1988) Arnold Wesker is a ventriloquist with multiple personalities. His puppet is a gangster named Scarface. Under the puppet's psychological influence, Wesker is a dangerous criminal and crime boss. It has been implied that the Ventriloquist suffers from multiple personality disorder.
Detective Comics #827 (March 2007) A new female Ventriloquist, called Sugar by Scarface, has surfaced in the page of Detective Comics and is hinted to be an old character long thought dead (as part of her face is shown to be scarred). She is a more compatible partner than Wesker, since Scarface no longer substitutes "b" with "g" and is much more compliant with Scarface's brutal methods. She and Scarface seem to have a relationship similar to the Joker and Harley Quinn. Her real name is revealed to be Peyton Reilly, the former fiance of a friend of Bruce Wayne and the daughter of a mob boss.