He's the psychopath you'd most want to grab a beer with but probably not the one you'd want giving you a ride home. Dennis Reynolds is a deviant within a gang of deviants, and for some time now he's been the subject of one of the most insane Always Sunny fan theories: Dennis Reynolds is a serial killer.
Shows as absurd as It's Always Sunny in Philadelphia often attract eager fan theories and construct long, winding, and weird inside jokes. But the best fan theories are the ones that actually make sense when you stop and think about it. While it's pretty easy to make a case that any and all of the Always Sunny main characters are mentally unsound, an examination of the evidence implies a more sinister side to Dennis. So let's do what Charlie Kelly does best and argue the case.
One of the essential ingredients for the making of a serial killer is an abusive or neglectful childhood. From what viewers know of Dennis's mother, Barbara Reynolds, she was a hyper-sexual gold-digger who was particularly cruel and callous to her daughter, Dee, and her husband, Frank. She and Dennis, on the other hand, seem to have had an extremely close bond that might have been a little too Norman and Mrs. Bates to be healthy.
His father, Frank Reynolds, is regularly shown to act entirely out of selfishness and greed. He manipulated his kids during their childhood by doing things such as wrapping up empty boxes for Christmas and buying their gifts for himself. He openly celebrates the death of their mother after their extremely hostile divorce.
Oh, and let's not forget Dennis's grandfather, the Nazi who took him to Nazi summer camp.
Dennis Reynolds is easily likened to many of the most infamous serial killers, and some of these comparisons are more blatant than others. Many have noted a general similarity between Dennis and Ted Bundy. Dennis, particularly in the earlier seasons, often comes off as a normal, charming guy. He easily manipulates women because he appears non-threatening, but underneath the facade is a psychotic mastermind.
An obvious parallel is found between Dennis and Buffalo Bill from Silence of the Lambs in the Season 3 episode "The Aluminum Monster vs. Fatty Magoo." After putting on lipstick in the mirror while listening to '80's music, Dennis dons a dress he designed. Topping off their similarities is the skin fetish, which has also given people cause to compare him to Ed Gein, who notoriously skinned his victims.
In Season 11's "Mac & Dennis Move to the Suburbs" episode, their suburban home essentially becomes The Shining, and Dennis becomes crazed killer Jack Torrance, blurred between reality and his own insanity and nearly driven to murder. Season 11 Dennis, in general, is much more crazed and less in control of himself than Season 1 Dennis.
Dennis's intense need for power within certain social groups, such as his old fraternity, or the cool kids at his high school reunion, draws to mind Patrick Bateman from American Psycho, as does his tendency to erupt into violent, manic fits of rage.
And, finally, the repeated references to freezers containing severed heads connect Dennis to Jeffery Dahmer. So what does it all mean? The repeated connections to serial killers could be the show's way of hinting that this theory is correct. Or it simply means Dennis has a lot in common with your average psychopaths.
So, if Dennis is a serial killer, who are his victims? One of the more popular theories originally put forward on reddit is that Dennis's first victim was Brian LeFevre. In the Season 8 episode "Frank's Back in Business," Dennis impersonates LeFevre, a businessman who left his wallet at the bar. What begins as a plan to get free baseball tickets evolves into an elaborate hoax with the aim of "getting off." For Dennis, "getting off" comes by way of "wearing another man's skin" and feeling his "inner-most wants and desires." Though he is being wined and dined for a business deal as LeFevre, Dennis is more interested in the game of becoming someone else. He's even ready to have sex with a young male golf caddy simply for the thrill of being Brian LeFevre. This demonstrates that under the right circumstances, Dennis is willing to completely suspend his own values and lifestyle to "get off."
In the end, it turns out LeFevre was stabbed by a crackhead outside of the bar. Not only does Dennis appear to find sexual arousal from this announcement, but he also has a history of crack addiction. Since the crackhead is never identified, it's possible that it was in fact, Dennis, who murdered LeFevre in the hopes of continuing in his identity.
Other evidence for this theory are the episodes preceding and following. In the episode prior, Dennis laments that he cannot feel. He seeks to fill some vacancy inside of him. At the closing of the episode, he witnesses his dead mother dug up in her grave, entirely bones, and has a severe emotional reaction. These circumstances would certainly set him up with enough distress to seek control through murder. In the episode following, Dennis is in a celebratory mood and wants to live life and go dancing. He hates that the rest of the gang wants to spend their time on a screen. He eventually comes to a revelation that he is a god. All of this would certainly qualify as a "high" following a kill.
Though Sunny goes where no other show will, it's often the darkest most sinister moments that viewers don't get to see. Which is why, if Dennis was a serial killer, they probably wouldn't witness him in the act. That being said, there's strong evidence to suggest that he's been killing behind the scenes for some time now. Now the next question, does he have an accomplice?
Season 6, Episode 1: "Mac Fights Gay Marriage":
Dennis: I'm having feelings again. Like some kind of fourteen-year-old kid. You remember feelings, right?
Mac: Yeah. I have feelings every single day of my life.
Dennis: Do you?
Mac: Are you saying you don't have feelings?
Many serial killers have antisocial personality disorder, which is less about how "social" one is and more about lacking basic human emotions of empathy and remorse. In the later seasons of Sunny, Dennis often finds himself bored or numb and yearning to feel, such as when he marries Maureen Ponderosa, or when he admits to carrying an onion around in his pocket in the event he has to fake real feelings.
While Dennis does demonstrate certain emotions, usually rage or lust, he often seems to be searching for something more to excite and fulfill him. Could that something be a new hobby, such as serial killing, perhaps?