“Dexter” may be all about Dexter Morgan’s (Michael C. Hall) life as a member of law enforcement trying to hide his own dark urges to kill, but it’s also about the killers he stops. His version of vigilante justice involves channeling his need to kill by murdering those who escape the legal system. He tracks them down, only acting once he’s sure they are responsible for the murders he thinks they are. It’s a bit of a warped way to view the world, but it works for him. Until the end of “Dexter: New Blood,” when he finally gets caught. Then it all gets … really complicated.

That said, he’s not the villain of the show, despite seeming like it. He encounters plenty of serial killers, even in his workplace, that are true villains for a number of reasons. Some are killers worse than him, trying to start an apocalypse or reproduce their first murder. Others had a direct impact on Dexter’s life, whether that’s manipulating who he is, or trying to kill his son. There’s plenty to choose from, but, from worst to best, these are the best villains Dexter faces in the franchise.

Appearing in the third season of the original series, Miguel Prado (Jimmy Smits, who left “NYPD Blue” behind to pursue fresh roles like this) is an assistant district attorney with whom Dexter interacts with at work. While on the surface he seems like someone who wants justice, in reality, Prado wants to enact harsh punishments on those he decides deserve them. Even if he’s wrong.

While Miguel wants to pretend he has a moral code, that goes out the window if something can benefit him. Though he knows an innocent man is in jail, Prado keeps him there because he doesn’t want to hurt his own pride. He’s manipulative, lying and cheating to get what he wants, which theoretically goes against everything he should stand for as a district attorney.

Dexter and Miguel do work together for a time, with Dexter bringing him into the fold and giving him a look into his process. However, things turn sour when Miguel can’t control himself. Dexter lets him kill someone, only for his “friend” to start killing innocents. That goes against everything Dexter believes in. That tips the scales from Miguel being an issue to him being a true villain, and he’s evil enough to make this list.

Oliver Saxon (Darri Ingolfson), also known as the “Brain Surgeon,” appears at the end of the original series as the main villain of the eighth season. He got his moniker because he takes some of the brain of each person he kills, and he uses an ice cream scoop to do it. Though this season of “Dexter” is considered the worst by us, Oliver is the high point of it.

Oliver is the one who successfully kills Dexter’s sister, Debra Morgan (Jennifer Carpenter), though others tried their hardest. That alone makes him one of the best, because he succeeded where others failed. He leads Dexter on a goose chase around the city as Dexter follows the victims as they pile up, only for Dexter to realize that the guy he’s looking for lives right next door. Oliver started killing at a young age, and even faked his own death to get away from those who knew his true nature. That means he knows how to hide in plain sight.

Dexter considered Oliver to be a perfect psychopath. While others on this list have empathy and emotions that appear at times, the Brain Surgeon isn’t one of them. Though he tries to mimic what he should feel, like playing the grieving boyfriend, it never comes across as genuine. Dexter ultimately uses that to his advantage.

Jordan Chase (Jonny Lee Miller) is the main villain of the fifth season of “Dexter.” On the surface, he’s a well-dressed, charismatic man that people like to talk to. However, what he’s hiding is a persona that leads a group of people called the “Barrel Girl Gang” who, as their name suggests, put girls in barrels as a form of torture before killing them.

He doesn’t carry out the murders — he just directs them. Jordan thrives on control, and that’s the thrill of it for him. Telling his followers what to do to the women they’ve captured is how he maintains power, and it’s what makes him the villain with one of the highest body counts of the series. It’s when he loses control that he takes matters into his own hands. It’s why he has technically killed one person, beating them to death when they wouldn’t listen to his orders.

Jordan makes this list because there’s never anything to physically link him to the kills. He doesn’t touch the women, he doesn’t help carry out the assaults or the murders. He makes someone else do it for him, setting them up to take the fall so he can keep his reputation crisp and clean. It’s perfectly calculated. 

Appearing in the third season of “Dexter,” George King (Jesse Borrego), known as the “Skinner,” is a serial killer Debra Morgan (Jennifer Carpenter) is trying to track down. He does exactly what his moniker suggests — skinning his victims as a form of torture.

George is detail-oriented and able to hide well in his day job as a tree trimmer. He uses it as a guise to report one of his victims, and also to stalk Debra to see what she knows about him. Skinning someone, while awful, is time-consuming and requires both attention to detail and patience, further proving that he’s just as calculated as the best “Dexter” villains. Maybe one that goes a bit too far with his victims.

While he wasn’t a primary villain for Dexter for the majority of his screen time, George makes the list because of his inherent nature. He spent time in the Nicaraguan military, interrogating people with torture as a tool. When he changed his name and moved to Florida, he started doing it as a way to get what he wanted, hurting people to try and find Fred Bowman (Mike Erwin), who owes him money. He uses the lethal skills he has to serve himself and his goals, but in truth, he just wants to continue torturing people like he did in Nicaragua.

Santos Jimenez (Tony Amendola) worked under drug dealer Hector Estrada (Nestor Serrano) and is an important figure in Dexter’s past. While he’s arguably the most important villain of “Dexter,” he’s stuck back in the second season. He’s the one responsible for making Dexter who he is. He completed the hit on Dexter’s mother, Laura (Sage Kirkpatrick), and is the reason Dexter had to watch her die. 

What makes him one of the best is not only did he brutally kill Laura and three others at the request of a drug lord, but he kind of got away with it. Because Santos was willing to give the police information on Estrada, he was placed in Witness Protection, rather than in jail, for his crimes. He killed at least four people in the “Shipping Yard Massacre,” and possibly others, too. Santos managed to avoid incarceration for it all, which is a rare feat. 

While that means he really did have important information on his boss, it doesn’t negate the fact that he didn’t face any real consequences for his actions. Even if audiences could believe that Dexter’s mother and the others were his first kills, he wasn’t quick and clean about it. He used a chainsaw and left her children in a pool of blood. It’s a horrific murder, which makes him evading prison even worse.

Ray Speltzer (Matt Gerald), also known as the “Minotaur Slayer,” appears in the seventh season of “Dexter.” Though it’s only for two episodes, he makes quite the impact because of how he murders people. Dressed in a horned helmet, he forces his victims, typically women, into a maze, hunting them down inside of it. Speltzer is literally replaying the Greek myth of the minotaur and the labyrinth. Ray is incredibly violent and depraved, and he in no way tries to hide that behind a charming personality. Audiences know exactly what he is from the start.

He’s not a major villain, but he’s one of the best because of how much he gets across in his short time on screen. Ray is vicious, strong, and hard to capture, and that’s clear in how he hunts his victims. When he gets away the first time, it takes four people to get him into police custody. Sure, Dexter is able to take him down, but it’s not by force.

Ray acts as an extra catalyst for Dexter and Debra’s relationship (Jennifer Carpenter), because Dexter has since lets his sister in on his process. She knows he’s a serial killer, and she’s not taking it well. Ray forces Dexter to forgo his usual carefully planned kill in order to save her after she attempted to take Speltzer on by herself. The siblings reconcile after Dexter finally executes Ray, although their relationship stays complicated.

Travis Marshall (Colin Hanks, adding another terrific “hey it’s that one guy!” role to his collection) spent the sixth season of “Dexter” trying to cause the End of Days with his murders. Though he appeared to be a meek and mild conservator, he believed he was killing in the name of God to bring on a biblical apocalyptic event. This gives him the clearest intent and purpose of the various killers Dexter encounters, but his methods were always changing. 

Travis tried to recreate religious iconography with his victims, making seven major “Doomsday Tableaus” inspired by the “Book of Revelation.” While he’s a stereotype that appears in plenty of crime procedurals — religious murders create instant complexity — Travis stands out because of his ability to convince others to work with him. He doesn’t have a place of power within a church, like most fictional cultish killers, but he still wields a ton of charisma.

Part of what makes Travis a good villain is that, at times, you can see who he is when the biblical delusions aren’t taking hold. He even let a victim go simply because she asked. Unfortunately, this was a moment he later considered to be weakness, and he went back after her. When he isn’t experiencing a break from reality, he comes across as a fairly average, empathetic person. Watching him shift back and forth, even while he’s committing a crime, is eerie. It makes him one of the best villains on “Dexter.”

Isaak Sirko or Volk, played by Ray Stevenson, who can thank “Rome” for his place on “Dexter,” is the leader of a Ukrainian crime syndicate called the “Koshka Brotherhood.” It’s a powerful role that makes him the main villain of the seventh season. Because of his high place within the syndicate, people are often sent after him and he’s forced to handle it. Those aren’t the only murders he’s responsible for. He regularly goes after Dexter, trying to kill the titular character three times before Dexter, by then an odd friend, lays him to rest at sea.

Part of what sets Isaak apart from others on this list is his empathy. Is he directing his associates to kill people? Yes, but the people working for him aren’t worthless in his eyes. He’s upset when their deaths happen and wants them to be remembered with dignity. It shows that, while he’s having them do his dirty work most of the time, he cares about them as people. That’s a lot different from how similar characters are portrayed in the genre.

Unlike other villains here, he comes across like a full person. Isaak is dynamic, with a clear personality and sense of humor that comes out even at the worst of times. He’s charismatic and powerful, and his actions feel surprising at times. He’s not a serial killer, but he’s certainly not a good person. That complexity always make for the best villains. 

James Doakes (Erik King) isn’t a serial killer — he’s a member of the police force that Dexter regularly interacts with. While Dexter is able to slide under the radar most of the time because he’s a member of law enforcement, James immediately clocks that there’s something different about their blood spatter analyst.

Unlike many of the other villains on this list, James is an active presence on “Dexter” throughout most of the original series, though he’s at his best during the first two seasons. He’s the first to rightfully associate Dexter with the Bay Harbor Butcher case, showing he’s got investigative skills even if it does make audiences want to root against him. Fans don’t want Dexter to be accused of being the cold-blooded killer James knows he is, which makes him a villain from the audience’s point of view.

James resorts to stalking Dexter to try and get dirt on him, which is quite a leap for a professional’s behavior. He’s using police resources to fuel what amounts to be a personal vendetta to prove his gut correct. Just because he’s right doesn’t negate how creepy and inappropriate his actions are.

While several antagonists from the original series pop up in “Dexter: New Blood,” the main villain, Kurt Caldwell (Clancy Brown), is a new addition. He’s known as the “Runaway Killer” because many of his victims were young women who ran away from home. His nickname has a double meaning because, after luring them home, he would have them run from him before he killed them. It was his way to consistently replicate his first kill.

As the mayor of the small town he lived in, it was easy for Kurt to cover up his crimes. It was only in death that the people he vowed to be an advocate for found out what he was doing. Being able to keep that kind of secret is impressive, especially in such a close community.

However, part of how Kurt is able to do it is because he carefully considered his crimes. He targeted a population who wasn’t integrated into the community. He encouraged them to come to his property under the guise of helping them. He gave them a chance at freedom, only to take it away. Then he hid the bodies in an underground bunker to serve as a trophy room. On all fronts, Kurt committed the perfect crime, and his only downfall was that Dexter knew what to look for.

Brian Moser (Christian Camargo) is the Ice Truck Killer on “Dexter.” He’s introduced in the first season, continuing to have an impact throughout the franchise. He has a particularly gruesome method of killing, draining the blood and then dismembering his victims before leaving them for people to find. He’s calculated, organized, and has his kills down to a science. He even has a refrigeration unit in his home to make it all work. Chilling.

Part of what makes Brian one of the best villains in “Dexter” is that he’s a mirror and foil to the protagonist. Brian and Dexter are biological brothers, and Brian represents a different path Dexter could’ve gone down. Sure, we know Dexter as a guy who channels his “Dark Passenger” into a form of vigilante justice. That’s not how Brian operates. If he were like his brother, Dexter could be using the voice in his head as an excuse to kill anyone he wants. It isn’t like mirroring (unless you’re in the evil mirror universe of “Star Trek”), but more like seeing yourself in a vastly different timeline.

Not only does he present something for Dexter to fight against, but as the first big antagonist of the show, Brian sets the tone for everyone who comes after him, making him our penultimate villain. It’s hard to compete against the brother Dexter has to take down, but there is just one person who outdoes Brian.

Arthur Mitchell (John Lithgow), known to “Dexter” fans as the “Trinity Killer,” is easily the best villain of the entire franchise. Not only is he the most prolific killer featured, having been a serial killer for several decades, but he’s the one that gets under Dexter’s skin the most. Arthur’s been in the game longer than Dexter and is always one step ahead, directly causing some of the biggest heartbreak in the show.

“Dexter” fans also believe Arthur makes the fourth season the best, adding to his ranking power. They’re right. As a character, he’s dynamic and complex in a way that keeps you watching, even when you want to look away. He’s crafted this perfect persona of a family man, a community pillar, and because of his age, no one suspects him. Secretly, he’s an abusive patriarch who uses community service as a cover to travel freely and kill people.

Like Dexter, he has a voice inside of him urging him on, which makes him think he and Dexter are on the same level. In actuality, he’s carrying out a cycle that always consists of four murders, meant to represent the deaths he experienced in life that led him to become a serial killer. He even includes Rita (Julie Benz), Dexter’s wife, as a part of his cycle before Dexter gets the upper hand. Without spoilers, that moment is, unfortunately, key to what makes him the very best villain on “Dexter.”