Summary

• Criminal Minds delved into the darkest corners of humanity, showcasing both horrific crimes and the FBI's pursuit of justice.
• Some unsubs were based on real people, leaving a lasting impact on fans and even affecting the actors portraying them.
• Memorable unsubs like Nathan, Jeffrey, and Anita & Roger Roycewood stood out for their haunting characterizations and disturbing motivations.

Through the darkest part of humanity, Criminal Minds spent nearly two decades exploring what makes humans tick. It did that through the unknown subjects that committed awful crimes and the committed FBI agents pursuing them. Every episode acted as a case-of-the-week format while longer mysteries could take whole seasons to unravel. While the Behavioral Analysis Unit always ultimately saved the day, some of the unsubs will live on in the minds of fans forever.

Many of the unknown subjects the BAU chase in Criminal Minds are considered the worst examples of humans, and what is scarier is that some of them are based on real people. Even the actors were often affected, as Mandy Patinkin famously left because of how the show left him feeling after filming. What makes some of the unsubs ingrained in a viewer's memory is when an actor takes the horrific nature of the character and gives it a life that sends shivers down a viewer's spine.

Nathan Harris

Anton Yelchin

Nathan is one of the most compelling unsubs of the entire series. That's because he's not actually an unknown subject. Instead, Nathan is very much a known subject and someone who hasn't even committed a crime yet. After listening to a lecture about the path to becoming a serial killer, he approaches Spencer Reid directly about his concerns.

Nathan believes that he meets all of the criteria for a budding serial killer, and he doesn't know how to stop himself. It's heartbreaking to see someone so sure that they're going to turn into a killer and desperate to get help because he doesn't want to turn into the very people he heard a lecture about. Ultimately, he ends up in a mental health facility for treatment, but his terror and Reid's comion make him stand out amongst the unsubs in the series.

Jeffrey Charles

Cameron Monaghan

He's not just a memorable unsub; he's a child.

Most of the unsubs throughout the run of the original Criminal Minds series are adults - and men at that - reflecting the statistics of captured serial killers in the real world. Of course, those statistics are born purely out of people who have been caught and don't for those who have gotten away with murder. That's why the ones who break the mold in the series tend to be incredibly memorable.

One of those is Jeffrey Charles. He's not just a memorable unsub; he's a child. Jeffrey has an intense dislike for other kids his age as a result of his father being a guidance counselor, and very little patience to deal with them. He takes a baseball bat to them in the woods outside of his small town, showcasing a lot of anger for one of the youngest unsubs in the series.

Anita And Roger Roycewood

Beth Grant And Bud Court

It would be nearly impossible to separate these two since the husband and wife worked as a pair for their nefarious criminal acts. The duo abducted children every year, using the kids they held captive to help them abduct even more victims. Working in a crematorium meant they also had an easy way to dispose of any bodies.

What's most memorable about this pair isn't their methods though; it's that their motivations are never revealed. Criminal Minds is always very good about delving into the traumas of the unsubs and just what the stressors are in their lives that send them down their dark paths. While many of the traumas can originate in childhood for the unsubs themselves, that's not always true, and the show goes to great lengths to explain how unsubs are made. The Roycewoods, however, never had their backstory revealed, making them some of the darkest of unsubs.

Stanley Howard

Michael O'Keefe

Stanley Howard is the kind of unsub who preys on his victims' deepest fears. He knows exactly what those fears are because he also happens to be their therapist. What makes him a particularly dangerous unsub is that he can learn everything about a person without having to use interrogation techniques, torture, or stalking them. Instead, people tell him their secrets freely. His patients offer up the very things he can use against them.

Dr. Howard is someone who is in the position to help people. His job is supposed to be helping people with the problems they bring to him. He's supposed to be someone people can trust with their secrets. His ability to take those secrets, bring them to life, and literally scare people to death, makes him a deeply disturbing character in the show.

John Curtis

Mark Hamil

Part of the memorability factor for John Curtis is that he's played by Mark Hamil. Hamil is a pop culture icon as a result of the Star Wars franchise, but he's also made a career out of playing against type. He's an incredibly versatile actor who consciously takes on roles that will leave an impression. He's voiced the Joker in a slew of animated Batman projects, for one. For another, he's one of Criminal Minds' most memorable villains.

The show labels Curtis as a narcissist, but he spends his time copying other serial killers. That earns him the nickname "The Replicator." This unsub doesn't have a single method of preference, making it hard to find patterns to link his victims together. As the Replicator, he's willing to try every murder method, which made him incredibly difficult for the team to catch.

Adam Rain

Brad Dourif

Most fans know Brad Dourif as the voice of the killer doll Chucky in the Child's Play movie series. Though he's appeared in plenty of other roles, Chucky is so iconic that he's been typecast as a villain or even been cast in roles as a red herring for the real villain. When he showed up on an episode of Criminal Minds, it was clear he was not an innocent bystander. Adam Rain was a serial killer who was also a collector.

He appeared in the Season 8 episode "The Lesson." Rain had the bizarre modus operandi of using his victims as marionettes until they died - and then he began again, finding replacements. Keeping what looked like living puppets for him to use as his own playthings made him a very dark character in a series that was already full of so many dark characters.

Floyd Feylinn Ferell

Jamie Kennedy

Jamie Kennedy is not the first person that movie fans think of when they consider serial killers. He has always been best known for comedy even though he's had his fair share of drama roles. His most well-known role is that of a socially awkward movie fan and one of the best friends of the final girl in the Scream movies.

However, in the Season 3 episode "Lucky," Kennedy appeared as a cannibalistic serial killer. He would capture and "tenderize" women before killing and eating them. This was discovered after he cooked and provided chili for the search teams looking for a missing woman. She was part of the chili, as he revealed to the BAU team when he was interviewed. He was such a memorable and weird Criminal Minds unsub that he returned in Season 13 as well.

Billy Flynn

Tim Curry

Played by Tim Curry, Billy Flynn remains one of the most twisted Criminal Minds unsubs for a couple of reasons. He is based on a real-life serial killer in Richard Ramirez, also known as the Night Stalker. Ramirez and his crimes have been highlighted in several true crime documentaries and provided inspiration for part of the storyline in American Horror Story: 1984. Ramirez was also called the Walk-In Killer and the crimes he is known to have committed took place in California in the mid '80s.

Billy Flynn was the unsub in a two-part Season 5 finale, a serial killer who used blackouts in Los Angeles to make it easier to pursue his victims. He traveled the country, killing people at random, and got away with it for a long time, often leaving one survivor who could never ID him.

Tobias Hankel

James Van Der Beek

Tobias Hankel was a serial killer from Season 2 of Criminal Minds and was almost the downfall of Dr. Reid. He was played by James Van Der Beek who was best known for his roles in teen dramas in the early part of his career. Hankel was labeled a delusional schizophrenic with multiple personalities. He was a happy child until his mother left, and his father became abusive and often tortured him. He developed multiple personalities to protect himself.

Hankel appeared in two of the best Criminal Minds episodes, "The Big Game" and "Revelations," and ended up abducting Reid and drugging him, causing the addiction that plagued Reid for a long time. This also haunted Reid because he saw some of himself in Tobias and couldn't save the serial killer from his demons. Though his time in the show was brief, his impression lasted much longer.

Benjamin Cyrus

Luke Perry

It's not often that Criminal Minds takes on the criminal activity of religious groups, or in this case, cults. Typically, the series is more likely to focus on one-on-one crimes instead of those that target an entire community. Because this type of storyline is so rare in the show, it already made an impression. Add to that the charismatic Luke Perry in the role of a cult leader when Reid and Prentiss go undercover to speak with him, and the story becomes even more compelling.

Benjamin Cyrus was such an important figure in Criminal Minds that even years after his death, he returned to haunt Reid and the BAU team. Loosely based on David Karesh, Luke Perry portrayed Cyrus as the leader of a cult-like community that ended up in a hostage situation that led to several deaths. Cyrus was such a revered figure for his people that they regrouped years later to kidnap Reid and Penelope–and attempted to use Reid as a sacrifice.