"What is the point of having free will if one cannot occasionally spit in the eye of destiny?"
— "Gentleman Johnny Marcone", White Night
Harry Dresden is a genius who matches wits with those who live in the dark world of The Dresden Files. It's only fitting then that several of his greatest foes and morally ambiguous friends stand out from the crowd.
By order of first appearance.
All spoilers are unmarked. You Have Been Warned!
- "Gentleman Johnny Marcone", real name unknown, is constantly putting himself in a position where it's absolutely necessary for people who hate him to cooperate with him, whether because he's the lesser of several evils or simply the only option. Even before getting involved with the supernatural, Marcone brought all of Chicago's organized crime under his control. When he does get involved with the supernatural, Marcone never fails to come out on top, repeatedly outmaneuvering and helping to defeat forces far more powerful and older than he is. Marcone even becomes the first mortal signatory to the supernatural Accords. Fully aware of his limitations as a man, Marcone is insanely prepared for supernatural threats and takes measures accordingly, frequently destroying threats that come for him. Marcone is also driven by a desire to protect innocent bystanders from harm, his iron will defined by a little girl who was once shot by a bullet intended for him. A complex, ruthless man, Marcone frequently shows why he is one of Harry Dresden's great allies and enemies often at the same time.
- Cowl is a black wizard implied to be a former student of Kemmler, seeking his inheritance. Unlike Kemmler's other students, Cowl admits to an open disdain of the vicious sadists he shared a mentor with. Intending to take and consume the Darkhallow for godhood just so that it does not fall to the depravities of the other Kemmlerites, Cowl unleashes the Wild Hunt on Chicago and deceives Dresden so he might kidnap Kemmler's former spirit of knowledge, the skull named Bob, to give him the Darkhallow ritual. Surviving its destruction, Cowl manipulates the vampire Vittorio Malvora to further weaken the White Court, with Dresden not even entertaining the notion that Cowl is gone after the plot is uncovered.
- Mab, Queen of Air and Darkness, is the serene and cold queen of the Winter Court Fae. Mab is a genius and patient plotter who can run her gambits over years and plots to eventually corrupt and turn Harry Dresden into her Winter Knight. Mab fights a constant fight against the omnicidal Outsiders and is always ready with a scheme to keep them at bay. Mab is also an expert at playing people and manipulates the end of the Red Court vampires through Dresden. Seeing through Harry's attempt to kill himself to get out of her deal, she saves his life and helps to forge him into a tougher fighter and warrior through Training from Hell. Mab also defeats Nicodemus Archelone by tricking him into sacrificing his daughter as a way to pay him back for an attack on her and her kin. Always calm and polite, Mab is always ready with a new scheme and plan to keep her on top and remains as both one of Harry's greatest allies and foes at the same time.
- Martin, a seemingly innocuous member of the Fellowship of St. Giles, is a former spy for the Red Court in the resistance against them. Seeing all the horror and evil committed by his former masters shattered Martin's loyalty, making him a triple agent out to destroy them whatever the cost. Sabotaging a duel between Duke Paolo Ortega and Harry Dresden to keep a war between the Red Court and the White Council of Wizards ongoing, Martin later leaks information of his comrade Susan's daughter with Harry for the plans of Paolo's widow Arianna Ortega, letting her set up a sacrifice to wipe out an entire bloodline with its youngest member. Martin then manipulates a betrayal of the heroes to trick Susan into killing him, turning her into a full vampire so Harry is forced to sacrifice her, the youngest Red Court member, to exterminate the entire bloodline in order to save his daughter, dying with full satisfaction at his plans achieved.
- The White Court vampire Lara Raith, having been sexually enslaved by her own father, the White King, overcomes his control and cripples him into an Empty Shell that she uses as a puppet while she remains the true power behind the throne. Lara then proceeds to manipulate the rival families of the White Court into attacking female magic users too weak for the White Council to notice, betting on the fact that Harry Dresden will get involved and wipe out all of the challengers for leadership of the White Court. Lara is a consummate manipulator, frequently employing the aid of people who have reason to detest her and getting them to work towards her purposes. Lara is also secretly a fighter in the Oblivion War, seeking to exterminate ancient beings far too deadly to coexist with humanity. Despite freely acknowledging herself as a monster, Lara has a conscience, even if she will happily play her family, friends, allies and enemies to secure her goals and remain in power.
- The Erlking, real name Lord Herne, is a hulking, armored bruiser who leads The Wild Hunt. The Erlking is an affable Blood Knight who enjoys the thrill of the hunt and battle and seeks to best Harry Dresden who he views as a Worthy Opponent. The Erlking can skillfully help Harry and Susan Rodriguez against the Red Court Vampires through a Duel to the Death. The Erlking later expertly fights Harry using various tactics before intentionally throwing the fight to give him control of the Wild Hunt to stop an Outsider ritual. At the ritual, the Erlking uses various tactics and tricks to help Harry defeat them even summoning a Killer whale to remove the water around the ritual's island location to help Harry get across faster. A skilled master at the battle, the Erlking is instrumental in helping round the Fomor during the battle of Chicago.
- "Lash" or the Shadow of Lasciel is a beautiful spirit of intellect created from Harry Dresden making contact with the coin of the Fallen Angel Lasciel. Lash tempts Harry with power and abilities as well as kind words into taking up the coin and joining her master. Lash also gains a genuine affection for Harry and helps him out by concocting ingenious methods to defeat his various foes. She also helps him deduce various facts about the mysteries he's investigating. Lash eventually starts to become more human thanks to Harry and helps against an Outsider empowered enemy before giving her life to save Harry.
- Odin is a mighty god who gave up his great power and immortality so he could protect humanity from harm. Odin is a master at setting up events to humanity's benefit and helps Harry in his endeavors. Odin takes many aliases to protect humanity using ruthless aims to safeguard their future. As his alias of Security CEO Donnar Vanderrung, Odin helps bankroll Gentleman Macrone's criminal empire to keep the city safe and helps give Harry the info to destroy the vile Red Court. Through his alias of Kris Kringle/Santa, Odin acts as the emissary for the Winter Court and helps aid them against the Outsiders as well as helping Harry to defeat them by helping manipulate him into taking control of the Wild Hunt. He will also gift Harry with vital knowledge that helps to aid him in his various undertakings, subtly stirring him into doing what it takes to win. Determined to protect the world from harm at any cost and with ruthless drive, Odin in all of his aliases makes his mark as one of the most successful and charming characters in the series.
- Goodman Grey is a Skin Walker-human hybrid who acts as a hitman and has dedicated himself to ridding the world of far worse evils. A Consummate Professional with keen skills and the ability to change tactics on a dime, Grey helps Harry outwit and play Nicodemus "Nick" Archleone, with Nick not realizing that Grey was on Harry's side the entire time that Nick had "hired" Grey. As the head of Monster LLC, Grey hunts down other criminals and brings brutal vengeance onto them for the price of a dollar, planning perfect hits and being able to think of new ways to succeed when obstacles pop up, even pulling one over on Macrone in the short story, "Monsters". A self-proclaimed "professional monster", Grey cuts his own way as a charismatic individual fully dedicated to his goals.
- "Zoo Day": "The Shadow" as named by Harry's Foo Dog Mouse, was raised with no affection as a weapon by harsher masters than Harry. Directing dark wizards and haunts against Harry and his daughter Maggie on their day out, the Shadow reveals himself as Mouse's stronger brother, taking advantage of the chaos to try to kidnap Maggie who is saved only by Mouse's dogged determination and willingness to sacrifice himself in defense of the little girl which wins the Shadow's grudging respect before departure.
