Batman has had a lot of animated outings such as "Batman Beyond" or the more recent "Batman Unlimited," but none have been as definitive as "Batman: The Animated Series." The show not only boasted groundbreaking animation, it was also incredibly well written, with many of its episodes focusing on deeper backstories for its characters; especially the villains.

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With this series, many Batman fans, young and old, got a fresh understanding of some of the Dark Knight's most iconic rogues as they went toe-to-toe with the Bat himself. Some villains were truly terrifying in their schemes, others were tragic in their origins, but they always ended up thrilling us in each episode. With that in mind, CBR has dipped back into our favorite cartoon and chosen the very best baddies to ever appear in the series.

16 Honorable Mention: The Phantasm

We couldn't justify adding The Phantasm to this list because she was only ever featured in the animated film, not the series. Nevertheless, Andrea Beaumont was another formidable addition to Batman's animated rogue gallery. Beaumont was actually Bruce Wayne's ex-fiancée who lost her father to a hitman named Jack Napier (later known as the Joker). After that, she donned the brutal persona of The Phantasm and went on a revenge spree in Gotham.

The Phantasm operated very similarly to Batman, but differed in her stance on killing. Bruce only succeeded in temporarily stopping her in pursuing her death wish upon the Joker, but ultimately Andrea takes the clown hostage and disappears. Regardless of her justifications, The Phantasm was a great villain because of Batman's helplessness to truly stop her. The emotional ties between the two proved far too great for Bruce to overcome, so Andrea ended up "winning" in her path to vengeance.

15 The Ventriloquist & Scarface

Arnold Wesker was introduced in the series as a weakling henchmen known as the Ventriloquist at the complete mercy of his puppet named Scarface. During his debut episode, Batman deduced that Arnold suffered from multiple personality disorder and Scarface was a second, more dominant persona in Wesker's mind. Scarface himself was the complete opposite of his puppeteer: mean, violent and flying off the handle at any little thing. He was regularly armed with a machine gun, as Wesker himself was too scared to wield a weapon.

Scarface and his Ventriloquist counterpart might have been a little on the sillier side of Batman's rogues gallery, but the show incorporated them well. Besides participating in heists or nefarious schemes, Wesker at one point even became rehabilitated during the series. However, the mobster legend he had created with Scarface had too great an impact on Gotham and he quickly relapsed into his old self. Ventriloquist only ever wanted to be rid of Scarface and actually succeeded at one point. This showed growth for a villain rarely seen in a kids show, and displayed more than just a run-of-the-mill crazy guy with a puppet, until his genuinely tragic relapse.

14 Mad Hatter

Jervis Tetch made many an appearance during "Batman: The Animated Series." He was introduced as a scientist who took on the Mad Hatter persona as a means to impress a woman (aptly named Alice), but quickly devolved into committing crimes for his selfish impulses. Mad Hatter often put people under mind control utilizing microchips to recreate "Alice in Wonderland" characters as his henchmen.

Perhaps his biggest claim to fame during the show was his scheme to trap Batman in an elaborate dream in an episode called "Perchance to Dream." In the illusion, Bruce Wayne's parents were alive and well, he was engaged to marry Selina Kyle and Batman was a completely separate entity. The Dark Knight eventually broke free of the fantasy, much to Tetch's dismay, since he was willing to give Batman the perfect life so he would simply leave the Hatter to his own devices. Instead, Tetch was thrown into Arkham time and time again, but still remains one of the few villains that actually tried to do something positive to Batman; albeit in a less-than-ethical way.

13 Killer Croc

Killer Croc was less of a true villain and more so a misunderstood bad guy in the series. Formerly a pro wrestler in the show, Croc was originally known as Waylon Jones. Jones looked far different in the series to his comic book iterations, with gray skin and light scales with razor sharp teeth. Croc looked less like a creature, which furthered his sense of being an outsider in the show, since he still retained his humanoid look somewhat.

Jones went through a series of events that tested his sense of morality when set against a society that treated him like a freak. Croc at one point ran away with a traveling circus and questioned his plans to betray them all when, unlike anyone he had encountered, they treated him like a family member. In the show, Jones wanted to be accepted more than anything, but his personal grudges against those who wronged him were hard to overcome. Eventually, he took more of a comedic role when Batman masqueraded as him for the classic episode called "Almost Got 'Im" and coined his go-to phrase, "Hit 'im with a rock!" Waylon however, was shown as far more than a mindless beast in "BtAS," and a villain that was able to physically overpower the caped crusader during their scraps.

12 Clock King

If you ever want to see a nightmare scenario for running late, look no further than the Clock King. A character known as Temple Fugate in the show, he was largely changed from his comic book iterations. Fugate was a stickler for keeping time, but had it run afoul when he took the advice of a stranger (who later became Mayor Hill) to stray from his schedule. Temple suffered the loss of his company after an unfortunate series of events and blamed Hill for it, thus taking on the persona of Clock King to get his revenge. Fugate used an elaborate scheme of timed traps and puzzles to enact his retribution on the Mayor and nearly succeeded until Batman intervened (of course).

What's interesting about the Clock King is that he was never begotten from Batman's interference, nor does he directly hate the Dark Knight. Fugate's beef lay with Hill long before he became a mayor, with Temple carrying a longstanding grudge against him. Sure, Clock King created traps to avoid the Bat, but he didn't seem terribly preoccupied with him. Fugate was a tragic, but very calculating villain with very specific tactics, who managed to make acts of crime run on time.

11 Penguin

Oswald Cobblepot was definitely one of the classier villains featured in "Batman: The Animated Series." Penguin often planned heists for priceless treasures like fabergé eggs or rare paintings for his forays in crime. Although Cobblepot had distinct tastes in avian wildlife and bird-themed.... everything, he was still a man of finer tastes. Penguin didn't often work alone, instead creating strong partnerships between other rogues to rule the city of Gotham.

Cobblepot was nothing if not a schemer. Always careful to toe the line of what was (and was not) legal, Penguin eventually opened his own nightclub in an effort to become a "legitimate businessman." Often his venue was a smokescreen of sorts for his more nefarious behind-the-scenes crimes, but he still liked putting on airs. Cobblepot may not have been the physically strongest to come up against Batman in his animated adventures, but he was a big-picture thinker, a quality that many of his cohorts lacked. This made him a dangerous villain in the show, because of his willingness to network with other rogues, establish fronts and craft large plans to dominate Gotham through the underworld.

10 Mr. Freeze

Another tragic villain in the "Batman: The Animated Series" universe, Victor Fries (a.k.a. Mr. Freeze) was a big part of the show's success. In his first episode called "Heart of Ice," Fries is introduced as a former research scientist who suffered a lab accident at the hands of his former boss Ferris Boyle. Freeze wagers a vendetta against Boyle, as he not only caused Fries' transformation, but also ended his work to save his cryogenically frozen wife Nora. Mr. Freeze puts the ice on Batman's attempts to stop him with his cold gun, but is eventually foiled by the caped crusader.

This villain's portrayal in the series is heartbreaking to say the least, as it shows Freeze as a tortured character that has become completely disassociated with humanity. Batman eventually develops an understanding with Freeze, as he knows how deeply wronged the former scientist is. Batman also sees to it that Boyle faces proper justice for his actions against Victor. In that, the animated Mr. Freeze has succeeded where many villains don't: he actually made Batman understand his point of view, which is a very dangerous prospect.

9 Riddler

Who better to test the mettle of the so-called "world's greatest detective" than the Riddler? Edward Nygma in the series was a game designer-turned-rogue after being ousted by his boss Daniel Mockridge and losing all rights to his best-selling video game. Riddler kidnapped his former boss and dropped him in an elaborate copy of the game's maze (with bonus death traps of course) for Batman to navigate. Even though the hero saved Mockridge, Riddler was steps ahead and escaped, leaving his old supervisor in a paranoid state, terrified of the villain's return.

Riddler was regularly a step ahead of Batman, something rare for many of the series' villains. Not only did he escape him once, he erased his public files, trapped Jim Gordon in a simulation and fooled Arkham's doctors into thinking he was sane enough for a release. Nygma briefly went on the straight and narrow working for a toy company, but was unable to resist baiting Batman again, citing that he's "the only one worthy of the game." Even if his schemes seemed silly in the show, Riddler regularly manipulated his victims and the viligante from a distance like pieces on a chess board.

8 Bane

Even though he only appeared as the main villain in a single episode of the show, Bane more than tested Batman both physically and mentally. The super serum-enhanced  rogue was hired to kill the hero by Rupert Thorne and went about it in a much more cerebral way than merely challenging the Dark Knight. Bane figured out that Robin was a weakness for Batman and kidnapped the youth to draw him into a trap. Once the caped crusader appeared to free his young ward, Bane engaged him in combat one-on-one, suspending Robin in a deathtrap behind them. He practically beats Batman into submission, ready to break him over his knee before getting caught by surprise with a batarang to his Venom serum controller.

What's great about Bane in the series is his ability to strategize against the Bat. Bane knew that Batman was not easily beaten nor drawn out, so he had to deduce carefully his enemy's weak point. His appearance spoke more to his intellect being on par with the world's greatest detective, as well as being incredibly strong. Even though he was predictably defeated, Bane was certainly one of the more imposing foes Batman came up against in the series.

7 Harley Quinn

It's hard to think of "Batman: The Animated Series" without including Harley Quinn to some degree. A character first introduced through the show, Harley has become an incredibly popular mainstay within every medium of the "Batman" universe. Quinn is known first as Harleen Quinzel in the show, a psychiatrist at Arkham Asylum who has the misfortune of falling in love with the then-incarcerated Joker. The clown prince manipulates her, distorting her view on Batman and justice, so that she eventually breaks Joker out of the asylum and joins him in his mad life of crime.

Harley is more of a petty nuisance in the show than a real threat most of the time, but does manage to keep Batman on his toes. She often launched surprise attacks on the hero when he had Joker or other thugs on the ropes. When she briefly struck out on her own and teamed up with Poison Ivy, they both went on a successful crime spree and bested Batman a few times. Harley was fiery, temperamental and bubbly during her appearances. She was a rare villainess in the way she got Batman to understand the struggles she suffered along her troubled path and showed that he genuinely cared about her recovery, even if he was irked by her presence.

6 Scarecrow

Ah, good ol' Jonathan Crane. This villain was introduced in the show as an ex-professor of psychology at Gotham University, who was fired after his experiments ended up terrifying his patients, raising more than a few eyebrows in his academic circles. Crane struck back at the school in the form of his Scarecrow persona, creating his own special fear toxin and committing crime (and fear) sprees.

Scarecrow fell into a line similar to that of the Mad Hatter, in which his bread and butter was trapping Batman within illusions of the mind. Crane managed to take it a step further, as he attempted to poison Gotham City's water supply in an effort to create mass hysteria. At one point, in an episode called "Dreams in Darkness," Scarecrow had even injected Batman with his fear toxin, which affected the Dark Knight so much that he was committed to Arkham Asylum. While there, he suffered numerous hallucinations of his rogues gallery. The Caped Crusader was able to overcome many of Crane's plans, however, but Scarecrow remains one of the villains most able to shake Batman hard enough to doubt his own sanity.

5 Poison Ivy

Everyone's favorite eco-terrorist, Pamela Isley, was known for enacting plant-based vengeance on folks who disrespected Mother Nature. Ivy first set her sights on District Attorney Harvey Dent for his greenlighting of plans to bulldoze an area of rare flowers for a future penitentiary. She managed to poison him through a kiss but failed to kill him. Once Batman foiled her schemes, she took to fronting a resort spa (yes, really) that would turn her targets into plants as retribution for their crimes against the Earth. Even more terrifying, Ivy eventually concocted a mini-factory of flora that could produce human-like clone babies that she would transform into giant mutated plant beasts.

Poison Ivy was never really interested in killing Batman directly, but would certainly pull no punches when presented with the opportunity. She often deployed poisonous or venomous plants that would attempt to devour, infect or otherwise dispatch the Dark Knight in a far more gruesome way than mere bullets would. Ivy was dangerous in her stalwart beliefs, however, and had a willingness to go to extreme measures to defend them, perhaps even more in the animated series than in her appearances in the comics.

4 Clayface

Another one for the "misunderstood and misguided" list of "BTAS" villains, Matt Hagen was a popular actor whose career was cut short in the series by a car accident. Hagen was then lulled by an experimental cream that could temporarily hide his disfigurements and change his facial appearance, at the cost of committing crimes while in disguise. Eventually, Matt became addicted to the product and, in his attempts to procure more, was dumped into a vat of the stuff. This transformed him into the villain known as Clayface.

Clayface was truly terrifying on many fronts. His body was a big hulking mass of putty that he could manipulate into weapons as needed. He was also able to change his entire outward appearance for short periods of time and travel incognito throughout the city. In one episode, Clayface was even able to create a completely separate being named Annie and used her as a scout. Hagen was a villain that struggled with his identity and was wracked with the loss of his path in the world. Batman may have been able to stop him once or twice, but Clayface was among the few that could (and often did) escape him easily.

3 Two-Face

Harvey Dent was slightly modified in the animated series, as he was portrayed as a childhood friend of Bruce Wayne for a number of years (something that has since become continuity in the comics). His split personality was something he struggled with, but he managed to suppress it with therapy. That is, he did until Mob boss Rupert Thorne attempted to blackmail Dent with his diagnosis to ruin the then-District Attorney's career. After a confrontation with Thorne, Harvey was caught in an explosion and netted his Two-Face scars.

Two-Face was mentally unhinged and unpredictable. His sense of justice was twisted and warped to rely on a simple coin toss to decide people's fate. In the series he was more than a victim of a mob boss, but a close friend that Bruce had lost to the underbelly of Gotham. Two-Face often posed a very real threat to opposing mob bosses and never backed down from a fight. He was willing to partner up or drive stakes in between his enemies depending on which side his coin landed. Harvey is a fantastic villain in this series for his brutal take on justice; a stark but measurable contrast to Batman's own stance. His revamped relationship with Bruce in the show also made his transformation into Two-Face all the more impactful as a stalwart enemy of Batman.

2 Ra's al Ghul

This leader of the League of Assassins was simply unmatched in his manipulation of Batman in the series. Ra's wanted to groom Bruce Wayne to be his heir to the League throne and went as far as creating an elaborate scheme to do it. Ra's al Ghul orchestrated the kidnapping of Robin as a ruse to test Batman's abilities as a potential leader of the Assassins. After the hero rescues Robin and refuses to side with him, Ra's attempts to blow up every Lazarus pit in the world to restore the numerous damaged ecosystems.

Ra's al Ghul is simply not a man to be trifled with. Having lived a number of years, his wealth of knowledge and experience was far more than what Bruce had. He was a figure working in the shadows that Batman could never fully defeat thanks to the Lazarus pit. He wasn't crazy (well, maybe a little bit thanks to the pits), but simply cold and calculating. He was willing to sacrifice numerous lives for the betterment of mankind and was unshakable in his ideals. As far as the threat he posed to people well beyond the Gotham City limits, Ra's al Ghul was a formidable villain indeed in the series.

1 Joker

While the Joker has been featured in a number of "Batman" movies, cartoons, video games, books and more, his portrayal in "Batman: the Animated Series" sits among the highest renown in terms of fan favorites. Voiced by Mark Hamill, the animated Joker was cunning, slimy and genuinely terrifying. His laugh made the hair stand up on the back of your neck, sending viewers staring with great anticipation at their screens to see what he would do next. This iteration was a mixture of his early goofiness and violent mobster origins. With the addition of Harley, the clown got a new depth of horror as he manipulated her regularly to do his bidding.

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Throughout the show, Joker's plans were as wild as his personality, from terrorizing a single Gotham-ite into doing his bidding in "Joker's Favor" to demanding a copyright to Joker Fish in a ploy to extort the city of millions in "The Laughing Fish." The only rhyme or reason to this villain's actions was that he expected, even wanted them all to end with a punch-up with Batman. The Dark Knight's greatest villain was not only great in the comics, but in this animated series, was adapted into something entirely amazing and unique on its own.

Who was your favorite BTAS villain? Let us know in the comments!