It's a peculiar thing that Gotham's most notorious villains are sent to Arkham Asylum as opposed to a regular prison. What sets Batman's Rogues Gallery apart from the others is that so many of them have tragic backstories that parallel his own, the difference being the paths they went down as a result of that baggage.
While so many of his enemies inspire sympathy, there are also many who are irredeemably evil. From abusers to abuse victims, the mentally ill to the mentally psychotic, Batman's villains often sit somewhere in between. Still, while they almost always have at least some shades of grey, most still tend to fall more squarely on one side or the other.
10 Sympathetic: Red Hood
Jason Todd as the Red Hood is one messed-up kid. The much-hated second Robin, murdered by Joker, resurrected by a reality punch, and healed by the Lazarus Pit, Red Hood is an angry man and essentially a killing machine.
While Red Hood is currently working to redeem himself with The Outlaws, he's no stranger to being an antagonist to his one-time mentor, Batman. Beating Tim Drake, becoming a crime boss, and being a general thorn in Batman's side, Jason is a complicated hero/villain/anti-hero who stirs sympathy.
9 Evil: Professor Pyg
A 21st-century Grant Morrison and Andy Kubert creation, Professor Pyg is no joke, even if his name elicits a laugh. Mentally ill and dressed in a pig mask, he uses surgery, chemicals, and lobotomies to experiment on his kidnapped victims to make them "perfect" and "pieces of art."
By design, Professor Pyg's victims become his Dollotrons: Mind-controlled, doll-like humans with masks permanently molded to their faces. What Pyg does to his victims is, according to Batman, a fate worse than death, making him quite evil indeed.
8 Sympathetic: Ventriloquist (Arnold Wesker)
While many of Batman's enemies suffer from mental illness, few are written to have a disorder as misrepresented and stigmatized as The Ventriloquist, who has dissociative identity disorder, formerly known as "multiple personality disorder."
Arnold Wesker is the first Ventriloquist, a meek and mild man whose alternate identity is Scarface, a crime boss in the form of a puppet. What makes Arnold sympathetic is not only the fact that Scarface is a murderer, but also the fact that his disorder is so misunderstood.
7 Evil: Victor Zsasz
A sadistic serial killer who likes to carve tallies into his skin to mark each of his kills, Victor Zsasz is a pretty bad dude. After his life fell apart and he was about to commit suicide, Zsasz was nearly assaulted by a homeless man. This led not only to his first murder but also to his perverse nihilism.
Most audiences know Zsasz as the brutal henchman to Black Mask in the Birds of Prey movie but he's more than a goon— he's true evil.
6 Sympathetic: Harley Quinn
As a henchwoman madly in love with The Joker, Harley Quinn was created to be a sympathetic Batman villain. Unconditional love in the face of an abusive partner who manipulated her all throughout Batman: The Animated Series made Harley an endearing character, which makes it no surprise that she is now one of the biggest assets to the DC universe.
While Harley is still a villain, she's written in a way that makes her more chaotic neutral than anything. Villain or anti-hero, everyone loves Harley.
5 Evil: Hush
A childhood friend of Bruce Wayne, Thomas Elliot had always been a bad seed. Not only did he cause the accident that killed his father, but he also murdered his mother years later in order to get his inheritance.
While he worked with The Riddler to destroy Batman throughout Batman: Hush, roping in many villains and superheroes to his twisted plans, his most notorious and diabolical act came in the "Heart of Hush" arc when he removed Catwoman's heart and put her on life support.
4 Sympathetic: Mr. Freeze
How far would you go to save your dying wife? For Mr. Freeze, he would do just about anything to save his ill wife, even becoming a great supervillain. Dr. Victor Fries' story of becoming Freeze is a tragic one that fans continue to find so endearing.
With his terminally ill wife frozen in ice while he tries to find her cure, the majority of Freeze's villainy stems from the goal to save her. While his methods are questionable, it's easy for fans to sympathize.
3 Evil: The Mad Hatter
Another Batman villain whose name elicits a chuckle, the Mad Hatter— also known as Jervis Tetch— is high up on the list simply for the fact that he is sometimes written to be disturbingly obsessed with children.
With his mind control powers, The Mad Hatter will kidnap children in order to have them dress up as Alice and the other characters from Alice's Adventures in Wonderland. There was even a story arc where Hatter was hired to kidnap children to sell into sex-trafficking, a completely despicable act with absolutely nothing to justify it.
2 Sympathetic: Poison Ivy
Out of everyone in Batman's notorious Rogues Gallery, Dr. Pamela Isley aka Poison Ivy, is the one who's been right all along. While she's always been depicted as a femme fatale who kills men with a kiss and cares more for plants than humans, her devotion to the planet has become more front-and-center and edifying as climate change in the real world has become impossible to ignore.
While she has no problem being called an "eco-terrorist", Poison Ivy's passion and the abuse in her past make her very sympathetic.
1 Evil: Joker
In just about every iteration of the Joker, he's the baddest of the bad. From murdering Jason Todd to paralyzing Barbara Gordon to orchestrating the death of a pregnant Lois Lane in Injustice: Gods Among Us, the Joker's list of evil deeds runs long.
Even when his characteristics are downplayed for laughs (his favorite) or we're given a semblance of understanding to his psyche like in the Joker film, there's still no denying that the Clown Prince of Crime is just pure, irredeemable evil.