The Blair Witch (real name: Elly Kedward) is the titular main antagonist in the movie The Blair Witch Project and its mythology.
The Blair Witch was an Irish woman named Elly Kedward, and she came to the United States of America in 1695. She settled in the small village of Blair in Baltimore and became a member of the community. In 1785, some children from the town accused her of luring them to her house to draw blood from them, and she was found guilty of being a witch, and was banished into the surrounding forest, tied to a tree, and left to die of exposure and starvation, it was assumed she died.
But her ghost returned and became the Blair Witch, an evil entity that haunted the forest and surrounding area. The Blair Witch was feared by many, and nobody would go into the Black Hills woods where she was said to live.
Settlers from Washington had found the ruins of Blair, which they renamed Burkittsville, after John Burkitt, the developer, and they built it into a settled town. They built a railway through the surrounding woods of the Black Hills. One day a young girl named Robin Weaver went out and got lost in the Black Hills and she returned three days later, babbling about an old woman whose feet never touched the ground. She had been lured away by the Blair Witch.
Although Robin returned, one of the parties sent to search for her didn't return, and they were later found gutted at the formation known as Coffin Rock and bound together. Pagan symbols were carved on them and they were still alive before being killed.
One day they were having a picnic to celebrate the settlement, and one girl named Eileen Treacle was mysteriously pulled into a shallow creek which was literally an inch deep. She mysteriously drowned and this was the first death to be blamed on the Blair Witch. Witnesses said they had seen a pale female hand pull Treacle into the creek, and it was clogged with oily Wiccan stick figures for days after.
The next incident surround the Blair Witch came in the early 1960s, when a local hermit named Rustin Parr came off his long solitude upon the Black Hills and came into town, and said he'd "finished." Parr's house was found to have the bodies of several missing children from the town inside. They bought all the bodies out and Rustin Parr confessed to everything and said that he had been haunted by the evil ghost of an old woman in black which he said was the Blair Witch. Parr was found guilty and hanged, saying the woman was never giving him any rest.
The Blair Witch returned in the 1990s when three students, Heather, Mike and Josh went into the Black Hills to research the Blair Witch legend as a class project. The Witch immediately began to cast illusions so that the teenagers got disorientated and couldn't find the way out of the woods. When Mike threw the map into the creek things got worse. The Witch began to mimic the murdered children from the 1960s in the woods and she left Wiccan stick figures in the woods for them. Finally the Witch came and abducted Josh, proceeding to gut him at night. Hearing his screams, Heather and Mike went to look for him but they are unable to. The next morning the Witch leaves a bundle of sticks outside their tent which Heather found contained gums, teeth, and hair, along the with blood-soaked scraps of Josh's shirt. Late that night, the Witch mimicked Josh's voice to lure Heather and Mike to her. They both search for Josh but found Rustin Parr's house, which had Josh's screams coming from it and the Blair Witch lured Mike and Heather down to the basement then killed them.
The following year the footage was found, and released to the public. It gained something of a following, with many tourists venturing into the woods in hopes to find the truth. One such tour group consisted of Stephen and his pregnant wife, Tristen, who are researching the Blair Witch for a book they are writing; Erica, a Wiccan; Kim, a goth psychic; and Jeff, their local tour guide. That night, they black out following an argument with another tour group, and awake to find their tapes missing, research torn up, and Tristen has had a miscarriage. After Tristen is discharged from the hospital, the group heads to Jeff's house, an old civil war factory, where they experience strange visions and find hours of missing footage from their tapes. Erica eventually dies, but when they call her parents, they claim not to have a daughter. Looking over the lost footage, They play the tapes in reverse to view the lost footage. The new footage shows Tristen leading them in an orgy and the ritualistic murder of the other tour group. Once the video ends, Jeff begins taping Tristen and demands a confession. She asks Stephen for help, but he claims that she deliberately killed their baby, so she ties a rope around her neck and Stephen shoves her from the ledge.
After this, Kim, Stephen and Jeff are interrogated by police in separate rooms and show separate tapes. In Kim's room, they play security footage from the store of her stabbing the cashier in the neck with a nail file. In Jeff's video, he kills Erica, arranges Erica's clothes and stows her dead body in the closet. In Stephen's video, they show him lynching Tristen, accusing her of all the death that surrounds them and cursing her as a witch. All three claim they never did any of those things.
Twenty years later, Heather Donahue's brother James examines the Blair Witch documentary footage his sister and her colleagues made before vanishing. James is convinced they are still alive so he, together with Peter, Ashley and Lisa, together with locals Talia and Lane. Lisa wants to make her own documentary from the quest.
For some reason (implied to be the Witch's magic) the crew oversleep until next afternoon. They also heard creepy noises in the woods at night. Lane and Talia are banished when they claim they created the Pagan Blair Witch figurines they encountered the previous night.
Ashley becomes ill because of a cut on her foot and Peter goes to get firewood but the Witch chases him and he disappears. The sadistic Witch mimics Peter's desperate cries which fade as James hears them and investigates.
Soon, Talia and Lane reappear, claiming they were lost for days with no sunrise, which sounds impossible. Lane runs off under stress of the Witch's magic. When they awaken, it is still pitch dark. Disbelieving that the Sun hasn't yet risen, they find larger stick figures around. Ashley berates Talia for creating the figures because of her role in doing such the day before and snaps one in half in anger, causing Talia to be ripped in half by the Blair Witch (the Witch is still unseen). The Witch (unseen) separates everybody and Ashley finds her aerial drone lodged in some trees. She climbs up but falls apparently to her death, while the Witch drags her offscreen.
James and Lisa find Rustin Parr's house, and James enters. Lisa sees the monstrous Witch emerging from the woods and, screaming, flees inside the house. James and Lisa find Lane, now aged, in the basement, saying he is under the Witch's control, and Lane attacks, but Lisa kills him in self defence.
The Witch performs her magic on the house which involves light shining in which soon disappears. Then the Witch enters the house through a mirror. She mimics Heather's voice, and kills James. Then Lisa hears the Witch mimicking James behind her, apparently apologizing, and she turns round, and gets killed by the Witch, who has now claimed Heather and her brother as well.