- In Sonic the Hedgehog Alternate Universe Fic Prison Island Break, Shadow the Hedgehog is a Serial Killer-Rapist. His crimes had a Power/Control motive. It was eventually revealed that he never actually enjoyed raping his victims, and the murders mostly happened when he lost control.Shadow: Eleven rapes, nineteen murders. And that's just what they caught me for.
- Scourge the Hedgehog is also a Serial Killer-Rapist, but with a much more Hedonistic motive.
- My Little Pony: Friendship Is Magic:
- Cupcakes casts Pinkie Pie as one.
- Cheerilee's Garden does the same for Cheerilee, though she tries to disguise her Hedonistic motivations as a noble crusade against the "weeds."
- Popped depicts Pokey Pierce, a fairly overlooked background pony, as a sadistic, power-thirsty serial killer that preys on young mares in and around Ponyville.
- The Pony POV Series has Dark World!Fluttercruel, who, while she doesn't mind how she kills a pony so long as its violent, her preferred method is akin to Cupcakes!Pinkie Pie; torturing them to death in her Torture Cellar. Her motivation is a mix of Power/Control and Hedonistic, as she enjoys the power over them and gets a thrill. However, her biggest motive she kept secret was that she kills to express her love for her father and due to being raised by Discord, she has no idea that what she's doing is wrong. Also the Supernatural type, due to being immortal, and Discord's demigod daughter.
- The Secret Life of Rarity is an example of a killer Rarity, dating back to a self-defense murder in her foalhood. She is a power/control killer, and by the end of the story she is the most prolific serial killer in the history of Equestria with well over 100 kills. Having said that, she has dissolved into clear self-loathing by the end of the story, and she hates how she has no control of her desire to kill.
- The Happy Tree Friends fanfiction "The Reaper" has one.
- In New Dawn, Nebiros is a Revenge Killer, taking very petty vengeance on those who he thinks were born into better circumstances than him. He also fits the Supernatural mold, due to the whole "he's a demon" thing.
- In a similar vein, most villains in New Dawn III are Serial Killers, the Big Bad being a Revenge / Mission Based Serial Killer. It's worse in Robin's case because his Modus Operandi leaves no trace of his victims behind.
- Ruby and Nora gives us Admah Keter, Nurse Abigail Lemon, and a supernatural serial killer in the form of The Wendigo.
- RWBY: Dark features a twisted take on Ruby Rose, who, after slaughtering her own parents and mutilating her half-sister Yang, seeks to become the most evil being in existence by becoming a serial killer and using her scythe to cut up anyone she comes across.
- SCP Containment Breach: SCP-106 uses the titular containment breach to go on a killing spree.
- Sleepwalker has confronted multiple serial killers who become supervillains. One example is Fever Pitch, a "visionary"-type killer with a large Charles Manson-like cult following who eventually becomes a living, flaming skeleton that can control and shoot fire. Another example is the Scarecrow, who murdered 16 people with a pitchfork before being caught and executed, but has returned in the form of a demonic Freddy Krueger-like monster that Mind Rapes his victims to death.
- Spider-Woman's Arch-Enemy, the Ax-Crazy Jack O' Lantern, counts as a serial killer simply based on the sheer number of people he kills over a period of several months. His reason for doing so? For the Evulz, mostly, which qualifies him as an "antisocial" type killer.
- The Bones fanfic "The Bard in the Bodycount" has Booth and the Jeffersonian team going up against a killer who stages his murders bases on scenes from William Shakespeare's plays. The first victim, for example, is a woman found floating in a river, her body clad in a shroud and strewn with pansies, rosemary, rue, and fennel, referring to the death of Ophelia.
- In the Doctor Strange fanfic "The Necessary Shadow", Doctor Strange starts hunting down a serial killer known as the April 9th Killer. Once a year on April 9th, he kidnaps, rapes, and tortures five teenaged girls to death in a ritualistic manner, and leaving their bodies surrounded by occult implements. This has been going on for seventeen years, and Doctor Strange is certain that the sacrifices have some occult purpose. It turns out he's right, but not in the way he suspects. The human sacrifice performed by the April 9th killer is actually preventing an ancient Eldritch Abomination from materializing and eating the earth. So in the end, as much as he hates it, Strange must allow the annual murders to continue...
- The Emergency! fic Lost and Found has a serial killer targeting firefighters. John becomes a victim when he pleads with the guy to take him instead of Roy, but survives because the guy wasn't solely a killer, he was also wanting a willing participant in his twisted games. John gets to the point of willingly complying because he's terrified of being tortured to death like the others. Still, he snaps when the guy says he's keeping him forever, and kills him to escape.
- Kitsune no Ken: Fist of the Fox has Utakata, a.k.a. Saiken the Slug of the Kyuushingai, who has killed 18 doctors and their families, plus anyone else unlucky enough to be nearby at the time, in the two years since the end of the 365 days' terror in which he was a participant. He's described as having been suffering from mental illness prior to receiving the Kyuushingai training, and describes himself as a psychopath. Turns out the doctors he targeted were all involved in the Kyuushingai training process, and more specifically they were the only ones who would have been able to prove that a major antagonist in the story was pulling a Dead Person Impersonation, which is why said villain manipulated Utakata into killing the doctors in order to keep the secret quiet.
- Pokémon Reset Bloodlines features a couple of examples:
- The Georgia Gaiden sidestory explores her background, about how her parents were killed by a murderer known only as "The Reaper", who left a distinctive mark is his victim's corpses. As it turns out, his real identity is the Striaton Gym Leader, Eric Knudsen, and used his Ghost-types to carry out his murders.
- In the Ultima Interlude, there's another that calls himself the "Bloodliner Hunter", who only targets bloodliners, convinced that he's on a divine mission to purge the world of them. According to Looker, he has eight confirmed victims and six unconfirmed ones, most of which were under sixteen years old.
- In Total Drama fanfic Monster Chronicles: Cedric is the Hedonistic type, who get sadistic pleasure in killing and mutilating his victims while operating under the moniker of the Mad Hatter Killer and the Zodiac Killer.
- In Destiny, Charlotte from The Princess and the Frog was murdered by a serial killer known as "the Shadowman".
Serial Killer / Fan Works