Normally, comic book characters make their debuts in printed media and work their way into live-action and animated TV series and movies. However, there are characters who did the exact opposite. When adapting comic book stories for the big screen or television, writers usually take the liberty of introducing changes to existing characters as well as introducing brand-new characters. Greg Berlanti’s Arrowverse has presented a number of original characters or amalgamations of existing comic book characters, such as Harrison Wells and Thea Queen. In the '80s and '90s, popular Marvel and DC Comics cartoons gave birth to new characters that did not exist in the comics at the time.

RELATED: 15 DC Characters You Had No Idea Were Already In The Arrowverse

Some of these made-for-TV characters received an overwhelmingly positive response from the fans, prompting Marvel and DC to give them their first appearance in the comics. Their small screen beginnings turned out to be their ticket to the mainstream comic book universe and some even ended up getting their own comic book series. Starting on TV, transitioning into comics and at times even migrating to the big screen, these guys sure know how to make a killer first impression. So, without further ado, here are the 15 characters you never knew debuted on screen first.

16 HARLEY QUINN

Harley Quinn Batman The Animated Series

Joker’s sweetheart, Harley Quinn, is one of the most beloved comic book characters, both in spite of and thanks to her insane personality. Portrayed by Margot Robbie, Harley Quinn recently made her live-action big screen debut in Suicide Squad. But this is far from being her only on-screen outing. In fact, Harley Quinn debuted on the small screen.

Harleen Quinzel started as an original character created in 1992 for Batman: The Animated Series. She first appeared in "Joker’s Favor" as a henchwoman to Gotham’s Clown Prince of Crime. Due to her popularity, the character soon made her way into comics. In 1993, Harley Quinn first appeared in a printed comic book in Batman Adventures #12, set in the DCAU. Her first appearance in DC Comics mainstream continuity came in 1999’s Batman: Harley Quinn.

15 FIRESTAR

Firestar Spider-Man and His Amazing Friends

The popular '80s cartoon, Spider-Man and His Amazing Friends, offered a variety of unique touches and quirky twists on our favorite heroes and villains from Marvel Comics. In this rather odd setting, Spider-Man joins forces with his roommates, Iceman and Firestar, to form a crime-fighting trio. The concept imagined Spider-Man with ice and fire teammates, but due to contractual unavailability of the originally planned Human Torch, the writers created a brand-new character named Angelica Jones, aka Firestar.

Firestar turned out to be popular enough for Marvel to bring her into their comic book world. In 1985, Firestar was introduced in Uncanny X-Men #193 and went on to get her own miniseries. She even became a member of the New Warriors as well as the Avengers, making her the first Avenger to have debuted outside Marvel canon.

14 CHLOE SULLIVAN

Chloe Sullivan Smallville

The fan-favorite, quick-witted and quirky Chloe Sullivan was specifically created for the TV series Smallville, mainly to fill the hole left by the absence of another self-assured reporter, Lois Lane. However, due to her popularity, Chloe continued appearing on the show even after Lois’s introduction and even spun off her own web series, Smallville: The Chloe Chronicles.

For a long time, there was talk about bringing Chloe into the mainstream DC universe, but the writers were hesitant because they weren’t sure how to retain the spirit of the TV character while at the same time making her discernible from Lois Lane. Nevertheless, in 2010, writer Nick Spencer finally gave Chloe her comic book debut in Action Comics #893, in a serialized Jimmy Olsen series titled "Jimmy Olsen’s Big Week."

13 MORPH

Morph X-Men The Animated Series

You can't have a superhero story without killing someone off right off the bat. Back in the 1990s, the writers of X-Men: The Animated Series wanted to raise the stakes and decided to kick things off with killing a member of the X-Men. However, since they didn’t want to lose an important character, they created Morph just to have him killed.

The cheerful and funny Morph was a beloved member of the team whose death had a major impact on the X-Men. However, it turned out that Morph’s body was stolen by Mr. Sinister who brainwashed Morph into believing that he should get revenge against his fellow X-Men. In 2001, a chalk-white, nose-less Morph made his first comic book appearance in Exiles #1. Luckily, he did not have to go through brainwashing the second time around.

12 LIVEWIRE

Livewire Superman The Animated Series

Livewire's recent on-screen appearance was on The CW’s Supergirl, where she faced off against Kara Zor-El. However, Livewire’s first TV appearance took place a whole decade ago on Superman: The Animated Series. Leslie Willis, aka Livewire, was created as an original character for the DC Animated Universe and eventually made her way into the comics.

Leslie Willis was introduced as a radio shock jock known for publicly criticizing Superman on her popular radio program Live Wire. Due to an electrical accident during a lightning storm, Leslie obtained the ability to manipulate electrical currents and took on the identity of Livewire. In 2006, Livewire transitioned into comics in Action Comics #835. Her background and powers were more or less unaffected, except that the comics version has possessed electrical powers since birth.

11 MELINDA MAY

Melinda May Agents of S.H.I.E.L.D.

Another TV debutant to make her way to comic book pages is Agents of S.H.I.E.L.D.’s Melinda May, aka The Cavalry. Agent May is a veteran pilot and soldier and a good friend of Agent Phil Coulson. After years of inactivity in the field, May returned to field duty on Director Fury’s request to secretly assemble a team for Agent Coulson. Initially tasked with keeping an eye on Coulson, May became an invaluable asset and Coulson’s right hand.

In 2015, Agent Melinda May made her first comic book appearance in S.H.I.E.L.D. Vol 3 #1. Her comic book counterpart was modeled after the actress Ming-Na Wen, who portrays the character on the show. Fun fact, the character was originally going to be named Althea Rice, however, after Ming-Na Wen was cast the name was changed to avoid the controversy of calling an Asian woman "Agent Rice."

10 WONDER TWINS

Wonder Twins The Super Friends

An animated superhero series titled Super Friends does not sound like a promising premise. This rather bizarre take on the Justice League is responsible for the creation of Wonder Twins, an alien brother and sister who must touch hands to use their shapeshifting powers.

Yet despite how mocked they were, these two somehow managed to make it into comics. In 1995, DC Comics officially brought the Wonder Twins into their mainstream universe in Extreme Justice #9, a 1990s' Justice League spin-off which ran for two years. In their subsequent comic book appearances, the twins’ background was revamped and they have been portrayed far more seriously ever since. Wonder Twins, Zan and Jayna, even made an appearance on the live-action TV series Smallville and the animated Justice League series.

9 LAURA KINNEY, AKA X-23

X-23 X-Men Evolution

Most of you probably remember Laura from this year’s blockbuster movie Logan: The Wolverine, but what you may not know is that Laura, aka X-23, did not originate in Marvel Comics. Craig Kyle and Christopher Yost originally created the character for the animated series X-Men: Evolution. Laura first appeared in season three episode titled "X23" as Wolverine’s young female clone.

The character was so well received that Marvel decided to make Laura an official member of their comic book family. X-23 made her first comic book appearance in 2004 in NYX #3, written by Joe Quesada and illustrated by Joshua Middleton. Once she migrated into comics, Laura quickly became a major character in the X-Men and even took on the mantle of Wolverine after Logan's death.

8 LEO FITZ

Leo Fitz Agents of S.H.I.E.L.D.

Scientist, genius engineer and S.H.I.E.L.D. Agent, Leopold “Leo” Fitz, made his first comic book appearance in S.H.I.E.L.D. Vol 3 #1. The character was created by Mark Waid and Carlos Pacheco in 2015 based on the personality and looks of the Marvel’s Agents of S.H.I.E.L.D. character of the same name.

Agent Fitz made his debut in the "Pilot" episode of ABC’s hit series Marvel’s Agents of S.H.I.E.L.D. back in 2013. The show’s popularity has led to a number of its original characters transitioning into Marvel's mainstream comic book continuity. Agent Leo Fitz gained wide acclaim and Marvel decided to introduce him to the world of comics. Apart from now being an official comic book character, Leo Fitz also appeared in Marvel’s animated series Ultimate Spider-Man with his colleague and friend, Jemma Simmons.

7 BARBARA GORDON

Barbara Gordon Batgirl Batman 1966

As surprising as it may sound, the 1966 Batman TV show is credited with the invention of Barbara Gordon, aka Batgirl. Although, a Bat-Girl and a Batwoman were created in DC Comics prior to the 1960s, they were abandoned for being too silly. The Batgirl most of us know and love is GCPD Commissioner Gordon’s daughter Barbara Gordon, who was created for TV.

Although Barbara first appeared in the DC Universe in Detective Comics #359, months prior to her on-screen appearance in "Enter Batgirl, Exit Penguin," her character was originally created for the Batman TV series. The show’s producer, William Dozier, created the initial concept for Barbara Gordon, aka Batgirl, which was further developed by Julius Schwartz, Gardner Fox and Carmine Infantino. Dozier created the character in order to appeal to female audience.

6 MERCY GRAVES

Mercy Graves Superman The Animated Series

Lex Luthor’s personal bodyguard and chauffeur, Mercy Graves, is one of the characters originally created for the DCAU who crossed over into comics. Mercy Graves was created in 1996 by Bruce Timm and Hilary J. Bader and made her first appearance in Superman: The Animated Series. Little was known about her life before Lex, except that she lived on the streets until she became Lex’s right-hand girl.

Mercy made her comic book debut in August 1999, in Detective Comics #735. Her background in the comics was slightly altered and it was hinted that she was of Amazonian descent. Mercy and a woman named Hope were hired to be Lex Luthor’s bodyguards during his time as President of the United States. After Lex lost the Presidency, Mercy remained by Lex’s side and even salvaged his career.

5 JEMMA SIMMONS

Jemma Simmons Agents of S.H.I.E.L.D.

Everyone’s favorite scientist duo, dubbed FitzSimmons by Agent Coulson, made its first appearance on the small screen, before migrating into comics. The genius biologist and S.H.I.E.L.D. Agent, Jemma Simmons, first appeared in the Agents of S.H.I.E.L.D. "Pilot" episode and has since grown immensely popular. Not surprisingly, Marvel decided to adapt her character into their mainstream comic book continuity.

Jemma’s comic book counterpart was created in the image of Elizabeth Henstridge, who portrays the character on the show, and made her debut in S.H.I.E.L.D. Vol 3 #1. In the comics, Jemma became a human cyborg after suffering a lethal infection that degenerated her body cells. Elizabeth Henstridge also voiced the character of Jemma Simmons in Marvel’s Ultimate Spider-Man animated series, where she appeared together with her partner, Agent Leo Fitz.

4 KALDUR’AHM, AKA AQUALAD

Aqualad Young Justice

The popular animated series Young Justice features several teenage superheroes trying to prove themselves as valuable members of the Justice League, led by Kaldur'ahm, aka Aqualad. Kaldur'ahm is an original character created specifically for the animated series, whose background was expanded upon in the show’s second season, focusing on his father, the Aquaman villain Black Manta.

After seeing the designs for Kaldur’ahm during the series production, Geoff Johns decided to transfer the character into the mainstream DC Universe. A slightly different version of the character appeared the same year in Brightest Day #4, a few months prior to the show’s premier. While Aqualad technically did appear first in the comics, the character had been originally created for Young Justice, but the show had a later premiere date than the comic’s release date.

3 JOHN DIGGLE

John Diggle Arrow

The success of the CW’s Arrow resulted in the expansion of the DCTV universe with four series, The Flash, DC's Legends of Tomorrow, Supergirl and Black Lightning. During its five-year run, Arrow has built a large fanbase and increased the popularity of Green Arrow comics. Arrow also contributed to the comics in the form of John Diggle, a character originally created for the TV series.

Former US Special Forces soldier, John Diggle, was introduced as Oliver Queen’s bodyguard who easily deduced the truth about Oliver Queen and The Hood. The two developed a close friendship and in season four, Dig became the vigilante codenamed Spartan. The character’s popularity led to his introduction into comics. In 2013, Green Arrow #24 marked the first official appearance of John Diggle in DC Comics.

2 RENEE MONTOYA

Renee Montoya Question Batman The Animated Series

The DC Animated Universe, especially Batman: The Animated Series, has had a major influence on the DC Universe in both comics and films. Detective Renee Montoya is yet another character that originated in the DCAU. Originally created by Bruce Timm, Paul Dini and Mitch Brian for the 1992 Batman series, Detective Montoya was a member of Gotham’s Major Crime Unite and occasionally partnered up with Harvey Bullock.

In 1992, Renee Montoya made her debut in Batman: The Animated Series. The same year, she also made her first comic book appearance in Batman #475 written by Alan Grant. In DC’s New 52, Renee took on the identity of the Question, following the death of her mentor Vic Sage. Recently, Detective Renee Montoya appeared on Fox’s Gotham as a GCPD detective and Barbara Gordon’s lover.

1 TERRY MCGINNIS

Batman Beyond Terry McGinnis

What happens to Gotham when there is no Batman to protect it? The answer is, Batman Beyond. Following the success and critical acclaim of Batman: The Animated Series, Warner Bros. went on to create Batman Beyond. The popular animated series featured an original DCAU character named Terry McGinnis who has donned on the cape and cowl in a futuristic and ruthless Gotham, under the supervision of an elderly Bruce Wayne.

Slowly but surely, Terry made his way into the mainstream DC Universe. After a number of cameo comic book appearances it was established that Terry took over as Batman on Earth-12 and Earth-992. In 2010, Terry McGinnis finally became part of the mainstream DC universe in Batman #700, where it was established that he will be the one to take on the mantle of Batman. Way to go Terry!

Which of these TV characters is your favorite? Let us know in the comments!