In stories it’s conflict that pushes the plot forward. In the case of superhero stories, it’s the villains. Without the villains, we’re stuck with a dry and boring hero. We might think that we want everything to go well for our heroes, but deep down we want them to have a struggle. If they could defeat their opponents in a single episode every time, there wouldn’t be much of a show to watch. Without villains we would be stuck reading/watching our heroes saving cats from trees or putting out fires and arresting petty criminals. They could have joined the police force or fire department if that were the case.

RELATED: 8 Useless Arrowverse Characters We Want Gone (And 7 We Desperately Want Back)

In The Flash we see each villain push Barry to be faster. Oliver is forced to outsmart his villains and the Legends need to beat the clock. In this list we rank the top 20 villains within the Arrowverse. That includes Arrow, The Flash, Legends of Tomorrow and Supergirl. As fans we want our villains to be as fleshed out as our heroes. We need them to pose a real threat, and maybe even be original if they can manage. Starting with the worst villain and ending with the crème de la crème of Arrowverse villains. Here we go:

20 SAVITAR

There was a lot of promise with the god of speed. He had a decent design in his silver armor with a blue glow, he had a partner in Doctor Alchemy, and he always seemed to be one step ahead of the Scarlet Speedster. He was even voiced by Saw’s Jigsaw himself, Tobin Bell. Everything felt on track for Savitar to be a better villain than Hunter Zolomon, or Zoom, was in the second season.

Then we get to the revelation, which was somewhat predictable by the fans, that Savitar was Barry Allen himself. Albeit a time remnant version of Barry, but Barry nonetheless. The producers continue trying to duplicate the appeal of season one with the mystery behind Harrison Wells but keep falling short. It’s a good thing they’ve decided against a speedster for season four’s main baddy. Maybe we’ll get something fresh.

19 CUPID

It’s understandable that the Green Arrow is going to have other archers as villains. We weren’t aware there were so many people good with a bow in the world, maybe it’s a mandatory class in Starling City public schools. However, when we get a villain that’s the embodiment of misguided love, can we agree to skip them and use someone else?

Cupid, or Carrie Cutter, was a former Star City police officer that became infatuated with the Arrow after he saved her from Slade Wilson’s attack on the city during the second season finale. She eventually fell in “love” with Deadshot after they worked together in Task Force X. Then he died and she went full villain, believing no one deserved love if she can’t have it. Does the Star City police department perform psych evaluations on their candidates?

18 ZOOM

Oh Zoom, you started out more promising than Savitar. We just came off of an amazing first season with an equally amazing twist for the main villain, and we were hoping for something close to that with you. Season one, Barry gains a mentor and mentor turns out to be a bad guy using Barry for their own nefarious deeds. Season two, Barry gains a mentor and that mentor turns out to be a bad guy using Barry for their own nefarious deeds. Do you see a pattern?

Let’s not forget that Zoom’s only motivation was to get faster. Talk about one dimensional. Yeah, he wanted speed to cure himself, but he only needed a cure because he created a serum to get faster. What was he going to do once he became the fastest man in the multiverse? Once you’re fast enough to outrun the cops, your job is done.

17 KILLER FROST

Everyone was waiting for Caitlin Snow to become the villain Killer Frost. We first encounter Killer Frost on Earth-2 working for Zoom. Getting to know Caitlin throughout season one and most of season two, it was difficult to imagine how she would go from the sweet, compassionate scientist to a homicidal maniac. Turns out getting powers turns you evil, which is why she is ranked as one of the worst villains in the Arrowverse.

It was poor writing as the frost powers weren’t psychological and didn’t affect her way of thinking. And if they’re going to do that to her, they should have the characters explicitly say something about it warping her mind in an episode. It just felt like the producers thought since she was a villain in the comics, they needed to make a villain persona for her in the show.

16 PROMETHEUS

Not too dissimilar from Savitar in the sense that he was always one step ahead of the protagonist, Prometheus was a good cautionary tale for our hero, Green Arrow. Prometheus dredged up Oliver’s past in the worst way possible by, for starters, being the son of a businessman Oliver killed when he first started his crusade as a vigilante. Then it turned out he went on to receive training from one of Oliver’s past mentors. Talia al Ghul.

He knew what made Oliver tick, how he would react to certain situations, and how to hurt him most. He was just too good, though. Wiring an entire island to blow, especially when that island is being used as a prison by A.R.G.U.S.? Just as we don’t want our heroes to be perfect at their job, we need a little believability from our villains.

15 TIME MASTERS

For a group of people that are supposed to be benevolent and omniscient, these guys really seemed to drop the ball. Well, maybe not. The cabal of Time Lords -- er, Masters -- was tasked with preserving the timeline, assuring that everything happened as it was meant to. It eventually turned out that the Time Masters were working with Vandal Savage and manipulating the timeline themselves.

Sure, it can be argued that they were doing what they thought was best for the universe, but it doesn’t take a psychologist to see that Vandal Savage only cared about himself and was working to benefit himself. When it comes to preserving life, or a timeline, it requires someone that isn’t concerned with profit and someone that would put a stop to a single man leaving death and carnage in his wake.

14 MAXWELL LORD

Because every Kryptonian needs a rich arch-nemesis, Supergirl had the founder and CEO of Lord Technologies. Maxwell Lord served as a recurring enemy in season one of Supergirl. Though he started the season being seemingly helpful, it would later be revealed that he wasn’t exactly the biggest fan of Supergirl’s.

He’s much like Lex Luthor in that he is a wealthy entrepreneur, targets a member of the El family from Krypton, and believes what he is doing is for the best for humanity. He doesn’t see himself as the villain -- they rarely do, though. Pretty sure when one creates a clone to kill and replace Supergirl, you’re the bad guy. The clone would eventually become twisted and corrupted by green kryptonite, turning her into degenerated form of Supergirl.

13 DAMIEN DARHK

As a former member of the League of Assassins, Damien Darhk thought it was best for humanity if he ended the world in a nuclear hellstorm to allow it to begin anew with himself and a select few as the founders of the new world. Darhk, after leaving the League of Assassins, would go on to create his own organization called H.I.V.E., who were Darhk’s own kind of League of Assassins, but followed more in line with Darhk’s own agenda.

He would eventually come to Star City where he would construct an underground community dubbed The Ark, where survivors of the orchestrated nuclear holocaust would reside and rebuild. While most of his appearances took place in Arrow, he would also go on to play a role in Legends of Tomorrow where he would be a member of the Legion of Doom. An apt name.

12 VANDAL SAVAGE

Vandal Savage is a man from 1700 B.C. that became immortal after a meteorite crashed into ancient Egypt. He would travel the world for years hunting Chay-Ara and Khufu to steal their life force. Oh yeah, he would also influence major historical figures that would create war and force technology to advance. He did this to prepare the world for his eventual rule -- it’s kind of a convoluted plot.

He doesn’t come into the top half of this list because, while the audience was told he was someone to fear, he didn’t portray that very well on screen. There was a timeline where Savage was defeated with the help of Flash and Green Arrow. Sure, he eventually regenerated from ash, but that could have been rectified. His comic book counterpart carries a far superior air of terror about him.

11 CAPTAIN COLD

Played by the always underrated Wentworth Miller -- best known for his role as Michael Scolfield in Prison Break -- Captain Cold is a classic Rogue of The Flash that fans desperately wanted to see when The Flash series was announced. He’s a calculating mastermind criminal that makes very precise decisions -- nothing is without meaning.

Seeing him as a recurring villain on the show was a no-brainer. However, did we need to see him become a hero or “Legend” or even a friend of Barry’s? Wouldn’t it have been much better for him to remain a villain and make an appearance as the main baddy for an entire season of The Flash? Also, we're still waiting for an episode that shows the previous cast of Prison Break to work together to break out of prison. That is a major missed opportunity.

10 HEATWAVE

Another former cast member from Prison Break, Dominic Purcell plays Mick Rory a.k.a. Heatwave on The Flash and Legends of Tomorrow. He ranks higher than Leonard Snart because Rory fought being a hero much longer than Snart did, and when he inevitably became a hero, he was a pretty awesome hero, easily one of the favorites on Legends of Tomorrow.

Heatwave was always a selfish person, wanting to rake in all the dough during his time on The Flash and still thinking of ways to score big while zipping around through time on Legends of Tomorrow. Then before he turned over a new leaf, he became the time-jumping bounty hunter Chronos that was hired to stop the Legends aboard the Waverider. After that, he became a snarky, likeable and valuable member of the Waverider crew.

9 LILLIAN LUTHOR

Dr. Lillian Luthor is the mother of the infamous Lex Luthor and adoptive-mother of Lena Luthor. She also happens to be the leader of Project Cadmus in Supergirl which conducts experiments on extraterrestrial threats. You can see how that’s not a good thing for Supergirl or Martian Manhunter. So it seems there is some bad genes in the Luthor genepool.

Lillian was embarrassed and infuriated with Superman after he sent Lex to prison for a very long time, so she took control of Project Cadmus and severed any ties it once had with the government. From then on she had been creating weapons, living and inanimate, to hurt or kill aliens of all kinds. So far the only decent living Luthor is Lena, the current CEO of L-Corp.

8 INDIGO

The first time we get to see a Brainiac on Supergirl, but hopefully not the last. Actually named Brainiac 8, she takes on the alias of Indigo when she arrives on Earth. Brainiac 8 was one of the most dangerous prisoners in Fort Rozz’s history, so her coming to Earth is not a good thing. Portrayed by Smallville alum, Laura Vandervoort, Indigo came to Earth wanting to exterminate humanity with extreme prejudice -- much like she wanted on Krypton.

This isn’t the same Laura Vandervoort we saw in Smallville where she wanted to follow in her Clark’s footsteps by helping the innocent. When her first attempt failed, she joined Non and helped him complete program Myriad. A program that allows its user to control the minds of any target they choose. In this case, the entirety of planet Earth.

7 DEADSHOT

Before he was killed off to make room for Will Smith’s Deadshot on the big screen, Deadshot was one of the most anticipated and loved villains on television. When the audience learned that he killed Diggle’s brother, we all knew it was only a matter of time before we saw him grace our televisions. He’s a master marksman and the world’s best assassin with a penchant for taking impossible jobs.

He was eventually captured by A.R.G.U.S. and imprisoned for a time until he was forced onto the Suicide Squad, also known as Task Force X. He went on a number of missions for Task Force X before he sacrificed himself for the good of the team. Laying down covering fire until his team escaped a building being surrounded by mercenaries, Lawton went down in the building’s explosion.

6 RA’S AL GHUL

Ra’s al Ghul is a name that resonates with comic book fans the world over. He is a popular villain that has gained prominence in multiple mediums including the comics, animated series and movies. Though Ra’s is typically seen going against Batman, he was a character being teased since season one of Arrow with the presence of the League of Assassins and his daughter Nyssa al Ghul, so it was only a matter of time before we got to see him go against Oliver Queen in some capacity.

Season three started very strong, too, and halfway through it was even stronger. His fierce and brutal fight against Oliver where he thrusted a sword through Oliver’s chest confirmed our suspicions that this was not a man for Oliver to trifle with. Unfortunately, his ferocity didn’t carry over to the second half of the season.

5 KING SHARK

The producers really pulled out a hat trick with this one, some might say they even “jumped the shark”. No one had expected the brief appearance of a giant great white shark/human hybrid appearing at the end of an episode of The Flash. Just as surprising as how easily he was taken down in that same episode, he was brought back for an entire episode of his own where we got to see him do more than just walk on screen and fall over.

The CGI used to portray this character was some of the best we’ve seen on the CW, which they have really been stepping up. Something one probably has to do when one of your recurring villains is a giant, telepathic gorilla. More on that later.

4 SLADE WILSON

Another popular character from the comics that fans got to see since the first season of Arrow is Deathstroke. We all thought we had seen him in the first episode with his iconic mask, but it turned out that was his former partner from the Australian S.A.S.. It didn’t take long for demand to catch up to the producers and show him in his iconic armor.

They nearly ruined his entire character, unfortunately, with the Mirakuru formula and his romantic feelings toward Shado. Not only did they present Slade as a professional soldier in the series, the comics establish him as someone that can put his emotions to the side to accomplish his mission. For example, in the comics he removed one of his own daughter’s eyes.

3 MALCOLM MERLYN

The very first long-term villain in the Arrowverse that could have made or break the entire design of the television universe for DC. Played by one of the greatest genre actors in the industry, John Barrowman played the Dark Archer with so much charisma and emotion, it was no wonder he was around for such a long time. He started off with a solid motivation for his devious plans and became a fully developed character by the end of the first season, unlike a few other long-term villains.

He was finally killed off in what could be argued as the best way for his character to exit the show, there is no argument that he probably overstayed his welcome on the series. While we’re sad to see him go, we’re not unhappy about losing any future father/daughter storylines.

2 GORILLA GRODD

This is a real missed opportunity for the producers if they wanted next season of The Flash to have a non-speedster as the season’s big baddy. Grodd, a former test subject of S.T.A.R. Labs’, has had some of the strongest episodes during The Flash’s tenure, and sure we have gotten a two-parter story arc for him, but this is a villain that is deserving of his own season.

With his brute strength, heightened intelligence and other psychic abilities, he can give The Flash a real struggle. He even has an army of giant gorillas he control. We’re sure we haven’t seen the last of Grodd, especially since he’s finally back on Earth-1, imprisoned by A.R.G.U.S., but he should have been the first choice -- best choice -- for the Scarlet Speedster's first non-speedster villain for an entire season.

1 EOBARD THAWNE

The producers did so many things right with the first season of The Flash and Reverse-Flash is one of them. They kept the audience guessing what was going on with Harrison Wells, wondering who was actually under the yellow mask, and how the Reverse-Flash was able to fight Wells if they were the same character. Revealing who was running around in the yellow suit didn’t disappoint either -- it brought more questions and intrigue.

His motivation, much like Malcolm Merlyn’s, was deep and believable. He was a well developed character that might have more depth to him than some of the protagonists on the show. It’s no wonder he keeps making appearances in The Flash and other shows. While the developers of the series know they did well with this character, they’re having quite the struggle replicating their success from the first season. Let’s hope season four finally succeeds.

Which Arrowverse villain was your favorite? Let us know in the comments!