Michael was first conceived when Tate, dressed as the Rubber Man, raped Vivien Harmon, who she believed to be her husband, Ben.  Psychic-medium Billie Dean Howard believed that a child born under these circumstances would be the Anti-Christ, and would be destined to bring about the End of Days. 
During Vivien's first ultrasound, the attending nurse fainted in horror at the sight of the then-unborn Michael in-utero, and quit her job immediately afterword; the ultrasound machine, mysteriously, broke moments after this.  Later, Vivien had a nightmare of a tiny clawed hand attempting to rip through her pregnant stomach, and soon after began to develop a taste for raw organs, consuming the liver and uncooked brain of a cow. Vivien was eventually able to contact the nurse from her failed ultrasound, who hesitantly agreed to meet her in a church, telling in her it was the only place where she "[felt] safe". She confided in Vivien that what she witnessed in her womb plagued her with nightmares and turned her into a believer in God, and, recalling what she witnessed during the ultrasound, whispered quietly to herself "...the hoofed feet". Vivien, thinking the woman to be mad, headed out the cathedral doors in frustration, while the nurse began to fervently recite quotes from the Bible, her face plastered with a look of dread. 
Personality and Appearance
Long before his preternatural birth, Michael gave every indication that he would be the personification of the most unimaginable evil to walk the Earth, prophesied by the Book of Revelations to conquer human life and unavoidably bring about the destruction of all of which does, and could, exist. From the moment of his conception - though only a rudiment in his mother's womb - he was a devourer of innocence: he fed off the nutrients of his twin brother to deprive him of a chance at life, and consumed the raw flesh of cattle to sustain himself in his mother's body before trading her life away, stealing her last breath during a violent and agonizing nativity that would only ensure his own successful emergence upon the world.  Even as a child, his very existence was a disturbing subversion of innocence, and he proved this at just six years of age, when he sliced open his nanny's neck to create frivolous handprints with her blood, giggling in the presence of his grandmother when she discovered the body.
Contrary to the Bible's proclamation that he would be the "essence of evil", however, Michael was not always devoid of humanity, and who he once was as a person was a direct opposition to what horrors he committed. His violent tendencies, while undoubtedly an innate part of his genetic makeup, were an aspect of who he was that he could neither control nor understand during his youth, resulting in him feeling confused and remorseful for unintentionally hurting the people he loved most. He had no recollection of attempting to strangle Constance , for example, and shed tears of regret upon realizing what it was that he was doing, leading credence to John Henry Moore's assumption that the Devil was possessing him . Despite Michael's best attempts to turn his uncontrollable murders into a positive, naming them as gifts in his grandmother's honor, he was unaware that the stress he put on her, as a result, would ultimately lead to her suicide - a fact that devastated him when he discovered her lifeless body, and would only hurt him even further when it was revealed to him by Ben that Constance no longer wished to see him as a ghost. Although Ben was not biologically related to Michael, he viewed him as the son that had been robbed of him by Constance, and bared witness to the boy's genuine tears of grief over losing the only family he ever knew. Longing to give Michael the life that he never had, Ben took him in as his own, and for a time, Michael finally felt at home again as the two grew close, laughing and smiling as they played baseball inside and talked about their shared values. Although Michael's biological need to murder still existed, Ben knew that it was not intentional on his part, and tried his best to ease those urges in him so that he could live as happy, healthy a life as possible. Unfortunately, these efforts would come to an end in Michael's first interaction with his biological father, who harshly rejected his son's eagerness to know him and shunned Michael as "something evil that even [he] couldn't create", leaving him alone to cry. Heartbroken at being denounced by both his grandmother and father, Michael began to sink further into darkness, causing Ben to start avoiding him out of fear. By the time the Satanists arrived, sacrificing an innocent women in his honor to retrieve her still-beating heart, Michael finally felt he was appreciated and consumed the tribute, at last fulfilling his role as the destroyer of mankind. Tragically, he has known no other way of life than his predetermined fate to end the world, and was only created by the Devil to serve as a pawn in the larger battle between good and evil.
In the ten years that Michael has since dwelt among mankind, he has come to fulfill his legacy as the Biblical destroyer, bringing about a thermonuclear apocalypse that kills off the majority of humanity and mutates the landscape. He is now all that stands between what is left of humanity and their extinction, viciously coercing what few survivors remain into giving in to their darkest temptations - lust, envy, greed, wrath, sloth, pride, and gluttony - while simultaneously concealing his true nature behind an innocent, almost angelic appearance. Due to his irregular growth rate, he has assumed the form of a handsome man in his early thirties with strawberry-blonde hair and striking blue eyes, and he uses this attractiveness to further manipulate his victims into turning against one another.  Ever since he was a baby, these human features were heavily implied to be a ruse, and this is confirmed when Michael confronts the witch Mallory and reveals that he is, in fact, a pale, emaciated being with deep-set black eyes.  Despite his vast supernatural powers, Michael seems to lacked the conniving, calculating and ambitious traits of his true father, Satan. He always need guidance and instructions from someone in order to work his schemes.
Vivien gives birth to him and his twin brother Jeffrey, who is stillborn. Michael is quickly snagged by Constance, and she and Moira admire him while washing off the placenta. This is interrupted by the ghost of Hayden who, angered by the loss of her own child due to being murdered, states that Michael will be her own baby and steals him. Hayden enlists the help of the ghosts of Dallas and Fiona to kill Ben before he can leave the Murder House for good, thereby preventing him from leaving with the baby; with all of the Harmon family now dead, she takes Michael for herself. Thanks to Travis incapacitating Hayden, Constance takes her grandson back and "adopts" him, moving to New York not long afterward. 
Sometime later, Constance comes home to find Michael sitting on a rocking chair in his room. The child, impressively already a toddler, smiles at his grandmother with blood on his face; he has murdered his nanny. 
Michael arrives at Outpost 3 eighteen months after several atomic bombs killed off much of Earth's life and brought forth a nuclear winter. The gates open to a carriage drawn by irradiated, pus-riddled horses, baring Michael as an agent of the Cooperative with an unlimited clearance. Ms. Mead disposes of the horses while Michael parlays with Ms. Venable, who's in charge of the refuge.
Langdon explains that he is there to evaluate the residents for possible transfer to the last remaining sanctuary, as six have been overrun and the remaining three beyond Outpost 3 are soon to be. He could take any, all, or none of them; those who do not meet his say-so will meet the same fate as his horses. 
After spending some time in Outpost 3, Michael introduces himself to the survivors and explains the situation that they are the last of civilization, and will be conducting evaluations to see who is worthy enough to be relocated to the impenetrable sanctuary, while the rest are doomed to either starve or be killed by the mutant survivors outside.
Michael first evaluates Gallant and inquiries about his homosexuality and hatred towards his grandmother Evie Gallant. Later that night, Gallant has sex with the Rubber Man, who he believes is Michael. Evie catches the two and reports them to Venable, enacting punishment. Michael reveals to Gallant that he was not the Rubber Man and that his grandmother was the one who reported him, thus releasing Gallant from his chains.
Michael then confronts Venable about her disregard for the Cooperative's rules and made-up rules against human sexual contact. He then forces Venable to strip and reveal her severed scoliosis. He reveals that neither she or Gallant will be accepted into joining him at the sanctuary. And according to his emails that were found by the survivors, he plans on executing the two. Later, Gallant is approached again by the Rubber Man, and he brutally kills him. Michael watches in amusement as Gallant discovers he was hallucinating and killed Evie. 
Michael continues to interview the people. He's surprised to find Dinah in the shelter. She reassures him that she doesn't have enough power to cause him any trouble. Michael says that he's looking for people who aren't pure of heart. He interviews Mallory about her desire to kill Coco, but she tries to flee. Michael forcefully grabs her arm, but Mallory pushes him away to the ground with an unseen force and coerces the flames in the nearby fireplace to burst near him. In shock and anger, Michael's human appearance alters, revealing for a moment that he is, in fact, a pale white demon with black eyes. Later, Langdon performs a ritual to talk with Satan. He cuts himself and begs for his father's help.
Michael is visited by Venable and Mead after they've gone through with their poison apple plan. He congratulates Venable on passing the test. Still, Venable tells Mead to shoot Michael. Instead, Mead shoots Venable. Michael asks Mead if she liked the poison apple plan because he had fun planning it. He explains to her that he commissioned her to be made and modelled her physical appearance after someone he used to know. He goes on to tell her of his plan. 
Langdon thinks back on his early life with Miriam Mead as he recounts the tale to robot Mead. He mentions how happy and protected he felt while in her care. He pauses as he senses Cordelia bring back Coco, Mallory, and Dinah. Langdon goes to investigate and faces Cordelia. He tells them that they'll all wish they were dead soon enough.
Three Years Before the Bomb (2017)
Langdon is in police custody after having stabbed a man. He did this because the butcher wouldn't sell Mead a goats head for a ritual. He's visited by Ariel Augustus who breaks him out and takes him to Hawthorne School for Exceptional Young Men. A month later, Langdon is being tested in order to evaluate his power level. He surpasses their expectations by completing each task presented before him. He finds a hidden book, teleports around the room, and makes it snow inside. The instructors are pleased by Langdon's accomplishments and later toast to him as they know his power will cause a shift in the magic community.
The instructors call an emergency council meeting where they tell Cordelia that they want Michael to take the Seven Wonders test. Cordelia is against it and refuses to administer the test believing that it would kill Michael as it did Misty Day. After having a vision, Michael decides to visit the Hotel Cortez and extracts Queenie from its clutches. He also visits Madison Montgomery and frees her from her own private hell. Queenie asks why he rescued them and he replies that he has to prove a point. They return to Hawthorne where Cordelia spots Michael approaching with Madison and Queenie in tow. She faints at the sight of them while Langdon smirks. 
When Cordelia awakes, she tells Langdon that he can take the Seven Wonders test in two weeks. The other warlock students gather around Langdon to offer their support so that he'll be successful in completing the test. John Henry Moore has his doubts about Langdon and leaves the school to go talk with Cordelia. He never makes it to New Orleans because Mead kills him at a nearby gas station. Later, Miriam recounts the tale to Langdon who is relieved. Now he can quit worrying about John Henry and focus on destroying the coven. Test day arrives and Langdon successfully completes all six tasks. When he comes to the seventh and final task, Descensum, Cordelia asks him to bring back Misty Day. The warlocks are angry because Cordelia is meddling with the test but Langdon agrees to do it. He descends and finds Misty reliving her school nightmare over and over. He kills the instructor and returns to the surface with Misty.
Langdon tells Cordelia that he did everything that she asked and completed all the tasks. Cordelia agrees and proclaims him the next Supreme. 
Due to his demonic heritage, Michael displays a variety of powerful supernatural abilities, on a higher level than even the Supreme Witch. Given his ease at mastering all Seven Wonders, in addition to other rare magical arts, warlocks have mistaken him for the legendary Alpha Warlock.
- Satanic Ritual - Michael is capable of performing sacrificial rituals by using his blood or other devices to create a pentagram that draws its power from his father, Satan.
- Illusion Manipulation - The magical ability to create, shape and manipulate illusions, causing others to see, hear, touch, smell and/or taste things which do not actually exist or cause them to perceive things differently from what they truly are. Michael is first shown using this power on Gallant, conjuring up a fake manifestation of the Rubber Man in order to seduce him and later drive him to a psychotic break, ultimately resulting in him murdering Evie.
- Conjuration - The magical ability to conjure objects and beings from other locations. Michael was capable of conjuring snakes and the Rubber Man.
- Satanic Conversing - After Michael discovers that Mallory is witch, he contacts his father, Satan, by telling him "I thought I killed them all, but one survived".
- Telekinesis - One of the Seven Wonders, the magical ability to manipulate objects with the power of the mind. After discovering Gallant strung up by his arms via chains attached to the ceiling, Michael reveals that it was Gallant's grandmother, Evie, who ratted out his sexual acts to Ms. Mead, resulting in him being tortured. Michael then uses this power to free Gallant from his constraints, knowing that Gallant would confront Evie about her betrayal. He also used this ability to break a jail guard's bones, torturing him till death.
- Transmutation - One of the Seven Wonders, the magical ability to instantaneously move from one location to another. This power was referred to as "Salire per spatium" by the warlocks.
- Clairvoyance - The magical ability to read the minds of others and project their thoughts into them. This power is also known as Telepathy. During the Scrying test, he read Baldwin's mind and learned which book he must look for.
- "Night Vision of the Soul" - The magical ability to "see into the dark places that people try desperately to keep hidden." He uses this power to sense Gallant's anger towards his grandmother and reveal to Mallory that he knows she secretly wants to kill Coco. It is likely Michael inherited this ability from his creator, The Devil, who mentioned in Asylum that he simply "know[s] everything".
- Divination - One of the Seven Wonders, the magical ability to gain knowledge through indirect means.
- Scrying - The magical ability to see things such as messages, visions, and prophecies on a reflective surface. He used it on a mirror in order to find a book at the behest of the warlocks, but he pushed it even further, shoving his hand in the mirror and pulling the book from it.
- The Sight - The magical ability to see the past, present and future by coming in physical contact with anything related to that moment, such as a person or object. By touching the incinerated corpses of Ariel, Baldwin and Mead, he was able to see their last moments, burning at the stake.
- Descensum - One of the Seven Wonders, the magical ability to descend into the netherworlds of the afterlife. This power is also known as Astral Projection. Notably, Michael does not enter a hell specific to himself, but has the unique ability to enter the personal hells of others. He can also carry someone along to travel through another's personal hell.
- Pyrokinesis - One of the Seven Wonders, the magical ability to create, control and manipulate fire.
- Soul Destruction - Michael has the ability to destroy souls, he has used this numerous times especially on witches.
- Concilium - One of the Seven Wonders, the magical ability to control the will of another.
- Vitalum Vitalis - One of the Seven Wonders, the magical ability to balance the scales of life and death.
- Resurgence - Michael can bring himself back from the dead, as seen after being fatally shot by Madison Montgomery.
- Power Negation - The ability to cancel out someone else's magic or voodoo curse temporarily. Michael was capable of breaking through a voodoo ritual cast by Marie Laveau.
- Stiricidium - The magical ability to control the weather, particularly through molecules of water.
- Bypassing Supernatural Restrictions - As the son of Satan, he can casually exceed supernatural restraints, such as setting a ghost free from a hellmouth or retrieving someone who did not return from Descensum.
- To Ms. Venable: "I've been assigned to evaluate the people here and select the ones most worthy of survival. I could take all of you, or none of you. Those who make it live. Those who don't, end up like my horses."
- To Gallant: "No need for rules anymore; Chaos has won."
- To Gallant: "If you lie I will know, if you try to trick me I will know."
- To Gallant: "The hole you need filled isn't in your face or your ass. It's in your heart."
- To Timothy: "You see I have a talent, call it a kind of night vision of the soul. I can see into the dark places that people desperately try to keep hidden."
- To Coco: "True darkness requires a certain depth of character. You're much too shallow for any kind of meaningful negativity."
- Ryan Murphy referred to Cody Fern, the new actor who will portray the adult Michael Langdon in the eighth season as: "...a brilliant addition to the cast. He appears to be as bad but more intelligent than the possessed Mary Eunice. Which is exactly what we need", implying a connection between Michael and the Devil from Asylum. This is strongly hinted at until directly confirmed in the episode Return to Murder House.
- During the season 8 premiere, Ryan Murphy jokingly described Michael's appearance as "Eyes like his Dad... Hair like his Mom."  However, Tate's eyes were brown, not blue. Murphy probably got confused with Ben Harmon.
- Michael's true demon form, though hinted at all throughout Murder House, is not directly seen until the events of Apocalypse . He is referred to as "The White-Faced Demon" by John Henry Moore and Cordelia Goode.
- See also: Michael Langdon/Media
- ↑ Episode: Pilot
- ↑ Episode: Spooky Little Girl
- ↑ Episode: Halloween: Part 1
- ↑ Episode: Piggy Piggy
- ↑ 5.0 5.1 Episode: Birth
- ↑ 6.0 6.1 Episode: Afterbirth
- ↑ 7.0 7.1 Episode: Return to Murder House
- ↑ 8.0 8.1 8.2 Episode: Could It Be... Satan?
- ↑ 9.0 9.1 Episode: The End
- ↑ 10.0 10.1 10.2 Episode: The Morning After
- ↑ 11.0 11.1 Episode: Forbidden Fruit
- ↑ 12.0 12.1 Episode: Boy Wonder
- ↑ Ryan Murphy on Michael Langdon's appearance (@MrRPMurphy) (2018-09-12).