Arrow has just returned to television for its monumental sixth season, and the hooded crime-fighter will now face off against the likes of Richard Dragon, a character well-known to comic book fans. Throughout its six year history, the series has proved to be quite the venue for characters hailing from all corners of the DC Universe. Both unlikely allies and villains have appeared on the series, from John Constantine and Christopher “The Human Target” Chance to the Teen Titans villain Deathstroke and the extremely lethal Prometheus, who turned out to be a very special twist on the comic book character.

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But this is only the tip of the iceberg. Arrow may have featured anyone and everyone from the comic books, but nowhere did it take more inspiration from than the Batman mythology. Whether it has used characters associated with the Dark Knight himself, storylines lifted straight from the Batman comic books or even the movies featuring the Caped Crusader, Arrow has borrowed from the Batman at every turn. Even in the series' early days; in fact, it the series was inspired by Christopher Nolan's Dark Knight Trilogy. Today, CBR travels back to Star City and lists 15 times the CW series used elements from the Batman mythos.

15 HEIR TO THE DEMON

In the comic books, Ra's Al Ghul spends a great deal of time in his prolonged life looking for a man worthy enough to be his heir. In the DC Universe, there is only one man he sees fit to fill in that role, and it's the world's greatest detective, Bruce Wayne. Ra's Al Ghul was teased in the first two seasons of Arrow before appearing as the main antagonist of its third season.

The Batman villain surfaced just as he was in the comics, with his cape and his Lazarus pit and his musings on life, except with one very noticeable difference: he sought to make Oliver Queen his successor, seeing the skilled crime-fighting vigilante as the one worthy to become the next leader of the League of Assassins.

14 COUNT JOKER-TIGO

The first Count Vertigo appeared in the first two seasons of Arrow. A departure from his more regal comic book counterpart, this take saw the character turned into a cruel drug dealer, one whose product flooded the Star City streets. But his quirky mannerisms, the high pitch of his voice and much of his attitude was very similar to another villain – one most closely associated with Batman: the Joker.

In fact, this Count Vertigo, who went by the street name “The Count,” borrowed a lot of inspiration from Heath Ledger's iconic take on the Clown Prince of Crime in The Dark Knight. Both had a propensity to make strange remarks and jokes, and both were presented as characters who were unpredictable, even in the presence of friends and allies.

13 FIREFLY

The first season of Arrow came back from its winter hiatus with "Burned," an episode that featured the threat of a one-off villain by the name of Garfield Lynns. That name is very familiar to Batman fans, because it's the alter ego of Firefly, the flame-obsessed villain. However, the series would change much of Garfield's story, choosing instead to make him a firefighter who was part of a team named the Fireflies.

If anything, this was more a re-imagining of what Firefly could look like in the Arrowverse, but it still doesn't change the fact that Garfield is first and foremost a Batman villain. Not only did he make his first appearance in Detective Comics, he was also featured in the Arkham video game series. And, to make it even clearer that this a villain associated with Batman, a new version of Firefly was even introduced on the Gotham television series.

12 OLIVER QUEEN: BILLIONAIRE PLAYBOY

In the pilot of the series, when Oliver Queen returned home after five years of being thought dead, he was a changed man who began a vigilante crusade. But to keep up appearances, the billionaire had to pretend he was still the man his family and friends knew him to be. To avoid suspicion, Oliver Queen returned to prominence in Star City during a lavish party where he played the unassuming playboy.

This is a cue taken directly from Christian Bale's turn as Bruce Wayne in Christopher Nolan's first two Batman movies, where Bruce would often find himself in social parties where he had to put on an act, to convince others that he was nothing more than a spoiled, rich, pompous man who would buy hotels on a whim or throw a fundraiser flanked by two super-models.

11 A SHIRTLESS DUEL WITH RA'S AL GHUL

Season three of Arrow reached a boiling point in "The Climb" when Oliver Queen found that he had no choice but to fight Ra's Al Ghul in a duel to save his sister. Knowing full well of his opponent's reach and abilities, Oliver still decided to go ahead with it, reaching the top of a mountain to fight Ra's Al Ghul in the snow. Both men dueled shirtless, armed with swords.

This is a direct homage to the famous shirtless fight between Batman and Ra's Al Ghul as seen in the Birth of the Demon graphic novel by Denny O'Neil and Norm Breyfogle, a fight that was also brought to life in Batman: The Animated Series. Stephen Amell himself went on to confirm that the scene was the show's way of honoring that classic Batman moment.

10 DEADSHOT

Very early on in the first season of Arrow, the hooded vigilante would go up against the likes of a character who made a name for himself in his first appearance in a Batman comic book in 1950, Floyd Lawton, aka Deadshot. Through the years, the hired assassin became an important part of DC's pantheon of characters, but he would always have roots as part of Batman's rogues' gallery.

The first big name super-villain that the Arrow would face on his show was actually a Batman villain. In the series, a rivalry of sorts would be established between the characters, much in the same way Batman and Deadshot have. Floyd would find himself recurring on the show for three seasons, and even became an important part of John Diggle's story, not to mention a member of Amanda Waller's Task Force X, the Suicide Squad.

9 BATMAN: THE CULT

Before work on the second season of Arrow began, it was revealed that the producers of the series had sent out copies of the 1988 prestige miniseries Batman: The Cult to their writers, as a thematic inspiration for the season. Written by Jim Starlin and illustrated by Bernie Wrightson, this comic saw Batman taken prisoner by an underground army, and it all led to all-out war in the streets of Gotham.

While this wasn't necessarily the exact premise of the second season of Arrow, there were similar beats, like Brother Blood's secret network, political heads being attacked, and Slade Wilson's army attacking the city in the finale. Season two wasn't an adaptation of The Cult, but it did prove to be inspired by the comic series in a lot of ways.

8 VERTIGO 2.0: FEAR TOXIN

After the first Count Vertigo died, a second stepped in to take his place in the season three premiere "The Calm," with a new twist on the Vertigo formula. Instead of doling out pain, it instead focused on fear. When injected with it, Oliver Queen imagined another version of himself, a dark reflection that he tried to fight off. This turn of events was very reminiscent of the Scarecrow's fear toxin.

As seen in Batman movies, video games and comics, the Scarecrow has a weaponized fear toxin that he can use to make others see their worst fears. Even the producers of the show were questioned about the similarity between this scene and the Scarecrow's weapon of choice; they said it was something that was simply coincidental. But the fact remains that they are still very much alike.

7 BE MINDFUL OF YOUR SURROUNDINGS

In season two of Arrow, Sara Lance, believed dead, resurfaced in Star City as the Canary after being trained by the League of Assassins. However, it didn't take long before a few of its members made their way to Star City to bring her back into the fold in the episode "League of Assassins." Sara, who now wishes to stay home, instead decides to fight them to remain free of their hold.

To do so, she sprang a trap on them. As she did so, she spoke a familiar phrase: “You should be mindful of your surroundings.” This is verbatim the exact line used by Liam Neeson's Ra's Al Ghul in the Christopher Nolan-directed Batman Begins, a phrase used more than once in the film. This is undoubtedly an homage to the film, and one that sparked many to hope Batman would show up in the series.

6 ANARKY

Anarky has never been a household name when it comes to Batman villains, but he's nevertheless been a part of his extensive rogues gallery. Introduced in Detective Comics in 1989, you can even see him in the current run of the title by writer James Tynion IV as a Gotham City rebel defying Batman's authority. This only adds one more name to the list of Batman-related characters Arrow has used.

On the series, Anarky surfaced in the fourth season as a low-level criminal, and he would recur throughout a few more episodes in seasons four and five wearing a mask similar to that from the comic books after becoming scarred. While he was brought on as an antagonist, the character somehow became more of a foil for Thea Queen than the Arrow.

5 COPYCAT ARROWS

After the devastating events of The Undertaking in the first season finale of Arrow, Oliver Queen returned to his island, leaving Star City vulnerable to its villains. This prompted the rise of The Hoods in the season two opener "City of Heroes," copycat Arrows who were inspired to do the same kind of work the vigilante used to do before disappearing. But they quickly proved themselves a dangerous threat to the city.

This turn of events is quite similar to Christopher Nolan's modern classic The Dark Knight, a movie that started with Batman going after the Scarecrow. But the battle revealed that there were a few ordinary Gotham citizens that had taken it upon themselves to become copycat Batmen, complete with hockey pads and shotguns. They proved themselves ineffective, and put themselves in mortal danger.

4 DETECTIVE LANCE: JAMES GORDON

Detective Quentin Lance has been a part of Arrow ever since its beginning, and while he went through many ups and downs and his character is now privy to Oliver's secret superhero life, there was a time when the police officer was on the hunt for the vigilante. Introduced as a foil of sorts to the Arrow, the character evolved into a reluctant ally, as the two men worked together to protect the city.

It's a relationship that borrows a lot from the one between Batman and Police Commissioner James Gordon, an iconic alliance that has been featured in the comic books and movies. While there may not have been an Arrow signal for Lance to call upon, the two of them did share many conversations on the rooftops of Star City as they traded intel, plans and tactics. And just like Jim's daughter would become Batgirl, so too would Quentin's daughter(s) become Black Canary.

3 HARLEY QUINN

Harley Quinn may not have had a big role in Arrow, but she did make a notable appearance. In the trailer for the season two finale of the show, "Unthinkable," we see the Clown Princess of Crime from the back, imprisoned in her A.R.G.U.S. cell as one member of Amanda Waller's Suicide Squad. Although the scene would ultimately be cut from the episode, we did hear Harley speak from behind closed doors.

Harley Quinn is a character firmly established in the Batman mythology, having been originally created for Batman: The Animated Series as the Joker's girlfriend. She then made the jump to comics as an important member of Batman's rogues' gallery and has been recognized as such ever since. It's therefore notable that she made a live-action appearance in Arrow before the DCEU.

2 THE GREEN ARROW RISES

When Oliver was believed dead at the hands of Ra's Al Ghul, he was missing for a long time. Criminals in Star City united and tried to seize control, and Team Arrow tried to hold them off as best as they could. Ordinary citizens joined in on the fight in the season three episode "Uprising," as two factions battled for the very soul of the streets, and it was only Green Arrow's return that would turn the tide.

This entire development is quite similar to the final movie in Christopher Nolan's Batman trilogy, The Dark Knight Rises. After being defeated and kept prisoner by Bane, Bruce Wayne could only watch as his city fell without the Batman. Citizens and police officers united to battle Bane's army in the streets, and with Batman's return, they finally stood a chance of winning.

1 TALIA AL GHUL

Talia Al Ghul, the daughter of Batman's enemy Ra's Al Ghul, has a long and complicated relationship with Bruce Wayne in the comic books. Allies, lovers, enemies, parents – they have been at each other's throats and in each other's beds. Together, they have a son, Damian, who has since gone on to become Robin. And yet, Talia made quite the splash in Arrow's fifth season.

Primarily a Batman-centric character, Talia made the jump to the small screen as one of Oliver's teachers in the past before turning up in the present seeking vengeance after the death of her father. Though they were never lovers, they were allies, then enemies, in another case of Arrow borrowing from the Batman comics to add to its own mythology.

What will Arrow take from Batman next? Let us know in the comments!