|“||Feast on this, motherfucker!.||”|
— Mia (to Abomination Mia)
She is the only survivor of the demon attack, having defeated the demons of the book.
Mia is 26 years old (born 1987) as said in the original script. She also was at her mother's deathbed, as David was not able to make it due to a new job in Chicago. Mia posed as David when her mother mistook her for him, creating a tension between the siblings. The traumatic event of her mother dying had a serious emotional effect on Mia; it is possible that witnessing her mother's declining mental state contributed to her drug addiction. She is superstitious and believes in protection from otherworldly forces. Because of her state when she saw her possessed self many times (while driving, in the water where she crashed and in the vine pit), nobody believed her when she told Eric, David, Olivia and Natalie.
In Evil Dead, Mia, David, Olivia, Natalie and Eric, go to Mia's parents' cabin in the woods. There, she decides to play "cold turkey" and dumps her heroin supply down the well. When suffering withdrawal effects, she smells something dead in the cabin, though no one else can seem to smell it. When the dog, Grandpa, begins to sniff the rug, they move it and find a bloodstained cellar door. In the cellar, Eric and David find dead cats hanging from the ceiling, and the Naturon Demonto (Book of the Dead) near a shotgun on the table. When Eric and David return upstairs, Mia admonishes them for bringing the book and the shotgun out of the basement.
When Eric reads a passage from the book, Mia sees a woman in a white dress calling her name in the woods. She runs inside, telling David and Olivia that she needs to get out of the cabin because she is going insane. Olivia tells her that they are not going to let her leave, because they think that she needs to stay in the cabin for a few days so that she can get clean, to which David agrees. Furious and feeling betrayed, she climbs out the bedroom window and hijacks Eric's car. Driving down the road, she sees the woman in white in her path, and swerves out of the way only to crash right into a swamp, knocking her out.
After regaining consciousness and escaping the wreck, she is chased by an unseen force. eventually tripping and falling into a vine pit .Then as she becomes trapped by vines that has thorns that seem to go in her skin. She then sees a possessed version of herself that chokes up a bloody thorny vine that goes up Mia's dress causing her to become possessed. Afterwards, David finds her curled up in front of an oak tree, scared out of her mind. Back at the cabin, she tells David that she thinks that there is an evil force in there with them, but everyone passes this off as an attempt to get out of the cabin because of withdrawal. David later goes into the cellar to remove the dead cats, taking the bag of cats outside, he finds grandpa their dog wounded by a hammer. At the moment there is a flashback of Mia beating Grandpa, a few minutes later grandpa dies. David goes inside the cabin to find Mia, Olivia then tells him she's in the shower, Mia burns herself badly in the shower by turning the hot water on full blast, fulfilling part of the Book's prophecy. David begins to drive her to a hospital, but is stopped when he finds that the road has become flooded by a river of fast moving water that is impossible to cross. Back at the cabin, Mia walks in with a shotgun found earlier, Mia shoots David in the shoulder with a shotgun, seconds before the unseen force bursts through the cabin door and flies to Mia. She screams as a demonic voice (implied to be Cheryl Williams) taunts the group, and remarks "You're all going to die tonight" in multiple simultaneous voices before falling to the ground. David tells Olivia to grab the shotgun but Mia grabs Olivia's arm as her eyes turn blue to yellow as she tackles her.
Suddenly, she attacks Olivia and vomits a river of blood all over her face. Olivia throws her into the cellar and Eric locks her in. Shortly after, Olivia goes off to clean herself up, but is then possessed by the demon. Said in the book, Olivia skins off her face with a knife as a worried Eric finds her. Olivia attacks him with the knife and stabs him multiple times with a syringe. Injured, Eric manages to stay alive and kills her with a large shard. David then treats his injuries and tells Natalie to get supplies from the kitchen. Natalie, hearing noises coming from the cellar, goes off to look. She then is tricked into entering the cellar with the possessed Mia. Attempting to escape, Natalie is pinned by the possessed Mia and bites into Natalie's left hand. Mia then proceeds to grab a box-cutter and splits her own tongue before kissing Natalie, but is interrupted by David, who forces them apart. The demon in Mia then states that Mia's soul is "being raped in hell." Angry, David chains the cellar shut.
Later, Natalie's hand becomes infected as it grows throughout her arm. She grabs the electric knife, intending to cut it off, but the possessed Mia opposes and screams in anger when she does it anyway. Meanwhile, Eric tells David that once the evil consumes five souls, the sky will bleed once again, and the dark one shall rise from hell. He also tells him that the only way to save Mia's soul is to kill her, either an alive burial, bodily dismemberment, or purification by fire. David is hesitant at first, until a possessed Natalie attacks the two men with a nail gun but not before firing several into her own face. During the attack she replaces the nail gun with a crowbar and is preparing to kill David when Eric distracts her using the retrieved nail gun. Unfortunately he runs out of ammunition and Natalie strikes him repeatedly in face and body with the crowbar until David uses the Shotgun to blow off her remaining arm. Natalie, who is no longer possessed, asks David, "Why are you hurting me?" and "Why does my face hurt?" then dies from blood loss.
After a while, David brings Eric outside the cabin. David, making up his mind, decides to throw gasoline all over the cabin to burn the place down. However, Mia begins to sing a lullaby when they were both young as children. Upon hearing this, David finds it impossible to kill her. Instead, he plans to bury her outside the cabin and collects a few supplies including sedatives. A moment later, he goes down into the cellar to capture her, but she attacks him with the box-cutter. She then throws him into the corner well and shoves his head underwater and begins to drown him. Suddenly, Eric appears and hits her over the head, knocking her unconscious, but not before getting stabbed by Mia's box-cutter which is one injury more than his already ravaged body can handle. David, now saved, mourns Eric's death.
As David begins to bury Mia, she wakes up as herself, telling David she couldn't breathe and panics. David continues to bury her, knowing if he releases her, she will attack him. Upon her death, David digs her back up and proceeds to shock her with defibrillators made from a car battery, seemingly unsuccessfully. David laments over the loss of his sister and walks away.
Mia, now free from the possession, awakens and calls his name, and the two embrace. After a short reunion, David tells her to wait by the car while he goes back inside to get the car keys. Inside, he grabs the keys, catching an eye of a picture of Mia, Eric, Olivia and him sitting on a couch, smiling at the camera. When David continues to turn around with a sorrowful look overcoming his face, he gets stabbed in the neck with a pair of pliers by a possessed Eric. David manages to escape as Eric watches him. Mia, seeing her brother injured, attempts to escape with him, but he opposes and proceeds to push her out the door and lock it. Despite Mia's screams, David shoots the canister of gasoline inside, igniting the whole cabin in flames.
A grief-stricken Mia cries, but finds the buckthorn necklace that David had given her. When she picks it up, the sky begins to rain blood. Suddenly, a hand shoots up from beneath the ground and grabs her wrist. Mia pulls away, frightened as she witnesses the Abomination rising from the ground. She then goes and runs to the car, but drops the keys while she tried to start the engine. The Abomination, breaking through the window, grabs and burns her leg, causing Mia to escape through the other door. Panicking, she crawls through the small hole where Grandpa, the dog, was found and finds her way to the supply room, where she obtains a chainsaw. The Abomination, finding her, attempts to attack Mia as she squeezes herself between a shelf and a wall. Injured in the shoulder and knee, Mia breaks herself out from the supply room, crawling underneath the car. As she starts up the chainsaw, the Abomination approaches the car, and loses both of her legs by the chainsaw. Mia manages to slip out from underneath the car, but The Abomination flips the car, as it crashes onto Mia's hand, forcing her to rip it off to escape. As the Abomination approaches, Mia picks up the chainsaw and shoves it into the Abomination's face, slicing her in half through body. It sinks back within a pool of blood in the ground as the blood rain ceases. Mia picks up the buckthorn necklace and wears it as she processes through the recent events before limping away. Just when dawn breaks over the blood-drenched woods, it reveals that the book that has started everything, flips itself closed. It is unclear whether the Abomination is defeated or if the cycle will be repeated.
In the original script, it states that Mia falls and a person in a car stops by, telling her if she needs help, they'll take her to the hospital.
- Mia's weapon of choice is found in the end, when she has to fight the demon. She chooses to use a chainsaw, which she shoves through the demon's head, killing it.
- Mia can be seen as a composite of both Ash and Cheryl Williams, however she shares more in common with Cheryl than she does with Ash, despite being the protagonist - both are the leading male's sisters, both are the first one to notice something is wrong, both get raped by the trees, both become possessed first and spend the majority of the film locked in the cellar and both stay as Deadites the longest. The similarities end as Cheryl is never unpossessed and is killed at the end of the original, whereas Mia's soul is saved and she becomes human again, surviving the final battle, where she becomes more like Ash.
- Mia delivered a one-liner similar to that of Ash's except it is when she faces off against her demonic self rather than the Evil Dead itself. She says" Feast on this, mother-fucker" While Ash simply says "Swallow this".
- A character in the video game Resident Evil 7: Biohazard named Mia attacks her husband Ethan with a chainsaw after she is possessed by Eveline, after he arrived in a house to look for her.