Comic book adaptations have plenty of reasons to add in their own original characters. To tell the story they want without an enormous cast, the writers might need to fuse various characters into someone new with certain traits or actions from those comic characters.

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They can also add new viewpoints and diversity. Diehard fans of the franchise still have to stay on their toes since the addition of new characters makes the story unpredictable. The key to a great original character is a backstory as thorough as any of their counterparts and a clear purpose in the plot.

10 Sara Lance

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There are seven different characters in the Arrowverse who operated under the name "Canary," but Sara was the first. Her sister, Dinah Laurel Lance, had the same civilian name as Black Canary did in the comics. Nobody expected Sara to become Black Canary because she was both not in the comics and supposedly dead. There were several fakeouts when it seemed Laurel was on the path to becoming Black Canary, but Sara beat her to it. It was only when Sara got killed again that Laurel took up the mantle.

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Sara was resurrected because that's kind of her thing and took Cisco's advice to become White Canary. Sara later joined the Legends of Tomorrow and became their captain. She was one of the seven Paragons during Crisis on Infinite Earths. Of all their original characters, Sara was the one with the greatest impact.

9 Alex Danvers

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In both the comics and the TV show, Kara Zor-El was adopted by the Danvers family after crashing to Earth. The big difference is that in the comics, the Danvers family did not include Alex. The Danvers were childless, hence their decision to take in Kara. One of the most pervasive themes of the show is sisterhood and the strength of their relationship.

The reason Kara even revealed her powers in public for the first time was to save Alex. Alex is an interesting character as she is one of the strongest non-powered fighters in the Arrowverse. They often use Alex as a foil for Kara in comparisons of power vs. skill or trust vs. cynicism. In the end, the two sisters always back each other up and love each other unconditionally. She's a great addition to the Superfriends and gives Kara someone to lean on.

8 Joe West

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When Barry Allen's father was arrested for the murder of his mother, someone had to take him in. In the 2014 show, that someone was Joe West, father to Iris, his best friend. This led to some interesting situations when they became a couple. Joe's job (besides being a detective) is mainly to encourage everyone, give them good advice, and tell it to them straight when they're being stupid. He has perfected the art of being what he calls a "dad cop." He's such an integral part of the family that it's hard to imagine The Flash without him.

The man who adopted Barry in the comics was officer Darryl Frye, who had been having an affair with Barry's mother. Iris's biological father was Erik Russell, a man from the 30th century who sent her back in time to escape nuclear annihilation, because nothing can ever be simple in comics.

7 Ryan Wilder

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The CW took a big chance on Ryan and it paid off. When Ruby Rose quit Batwoman after only one season due to injury, the showrunners' plan fell out the window. Rose's Batwoman, Kate Kane, was clearly being set up as a big player in the Arrowverse. She had a suitably dramatic entrance in the Elseworlds crossover and an important role to play during Crisis as the Paragon of Courage. She also had her own show, which was previously set on a different Earth, relocate to Earth Prime alongside all the other heroes.

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The loss of Ruby Rose could have brought all those plans tumbling down and the showrunners had a choice to make-- recast Kane or switch to a new Batwoman entirely. They chose the latter, but instead of picking another Batwoman from the comics, they created their own: Ryan Wilder. While some fans voiced dissatisfaction, Javicia Leslie's episodes consistently rate higher than Ruby Rose's.

6 Jeremiah Holt

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There are plenty of causes to fight for in Freeland, and Reverend Holt committed to pretty much all of them, including an "Underground Railroad" for metahumans and the Free Clinic. He actively opposed The 100 and Tobias Whale. A well-meaning man, he often set off important story events he wasn't even aware of. It was at Holt's rally that Khalil was shot, which led him to become the villain Painkiller.

The Reverend served as the face of Freeside and was unafraid to confront gangs and criminals. Even Jefferson couldn't fulfill that role in his civilian identity because he couldn't let his family become a target.

5 Thea Queen

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Thea was Oliver's half-sister and she spent the first few seasons as a spoiled rich girl. Fans of the comics recognized her nickname, "Speedy," and knew she was destined for more. Speedy is one of Green Arrow's comic sidekicks, also known as Mia Dearden. Her backstory is quite dark. Mia lived on the streets after running away from her abusive father until Oliver took her in. She was his ward and thought of her as his daughter. He trained her in archery but refused to take her as a sidekick, not wanting to put her in danger.

Once she discovered she was HIV positive, Oliver finally relented and allowed her to be his sidekick. Turning Mia into Thea and making her connection to Oliver a biological one was a good way to give them a strong bond without adding another dark backstory to an already bleak show.

4 Felicity Smoak

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While it's not entirely accurate to say that Felicity Smoak wasn't in the comics, that Felicity and the one on Arrow are completely different people. She appeared in the Firestorm comics. The rich manager of a computer software firm, the middle-aged Felicity was not a fan of Firestorm due to his recklessness and the collateral damage from his fights, which usually ended up somehow damaging her property.

Unlike her namesake, the show's Felicity is young and friendly. While some people disliked her relationship with Oliver, Team Arrow couldn't have accomplished what they did without her hacking expertise and she also provided some much-needed levity.

3 Mia Smoak

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Since Felicity and Oliver weren't a couple in the comics, their daughter would have to be an original creation. Mia, a cage fighter from the future, had the best traits of both her parents.

Trained by Nyssa al Ghul, Mia showed an aptitude for archery and hand-to-hand combat. Signs of Felicity's intelligence shone through when she managed to use clues from a documentary to find the old Arrowcave. Most importantly, she had more than enough angst to be the next Green Arrow. After Oliver died, Mia was supposed to take up the mantle in Green Arrow and the Canaries, but the spinoff show was sadly canceled.

2 Nia Nal

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Nia Nal made history as the first transgender superhero on TV and her story resonated with a lot of people. Nia is based on a comics character, Nura Nal, and has the same powers. Brainy later reveals that she is Nura's ancestor, explaining the similarities.

While Nia's gender plays an important role in her character, she's also a kickass superhero who took down a Dominator solo and stopped a tidal wave from destroying National City during Crisis. The issues of transphobia and harassment come to the fore in the episode Reality Bytes, which involved someone attacking trans people to lure her out. Nia is brave in ways that other heroes aren't because they simply don't have to be. Even with Supergirl coming to an end, Nia has firmly established herself in the DC Universe and she still has more lessons to teach.

1 Harrison Wells

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Harrison Wells was originally introduced as the surprise alter ego of the Reverse Flash, shocking new viewers and old fans alike. After another Wells from Earth-2 showed up, it became a running joke to continue adding new versions of Wells into the story.

By consequence, he is not only the most prolific character in the Arrowverse, but also a convenient stand in for other important characters. They are responsible for the creation of metahumans, closing the breaches to Earth-2, kicking off the Crisis, and reviving the Speed Force.

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