Dean's Crossroad Demon

This demon was among Crowley's "employees". She was called "the crossroad demon" in the show, but she is here nicknamed "Dean's crossroad demon" due to the later addition of many other crossroad demons into the show.

The demon was summoned twice by Dean: first to break one of her contracts, and later to sell his soul in exchange for Sam's resurrection. Shortly afterward, she was killed by Sam when she refused to break his brother's contract.

Background
In 1930, the demon was summoned by Robert Johnson to Rosedale, Mississippi. She agreed to give him musical talent as part of a deal, which she then sealed by kissing a surprised Robert. Ten years later, he died of a heart attack while being terrorized by hellhounds.

In 1996, the demon was summoned by George Darrow and made a deal for his soul in exchange for giving him artistic talent. After they sealed the deal, she spent a week hanging around a bar called Lloyd's, where she made three more deals with unsuspecting humans: Sean Boyden for architectural talent and success, Silvia Pearlman for success as a surgeon, and Evan Hudson for his wife's health.

The demon had heard about the Winchesters beforehand, including that John had sacrificed himself as part of a deal to save Dean's life.

Season 2
The demon was summoned by Dean in "Crossroad Blues" as part of his attempt to save Evan from his contract. She refused to spare Evan, and tried to manipulate Dean into making a deal for John's resurrection instead. Although he appeared to consider it, he was actually trying to lure her into a devil's trap; once she realized this, she was enraged and threatened to kill him, but then decided to let him live on in his misery upon realizing that he had a death wish. Again feigning a desire to make a deal for his father, this time Dean succeeded in tricking the demon under another devil's trap he had prepared. She finally agreed to break Evan's contract after Dean started exorcising her.

Incensed by Dean's actions, the demon described to him the pain his father was undergoing in Hell, and told him he should have taken the deal she had offered him. She quickly left her host when an upset Dean went to exorcise her anyway.

After Sam was killed in "All Hell Breaks Loose - Part 1", the demon was summoned by Dean in "All Hell Breaks Loose - Part 2" to try to convince her to resurrect Sam. She relished in Dean's despair and took pleasure in repeatedly rejecting his offers at a deal, claiming that his soul was too tarnished to want. However, she eventually relented and agreed to bring Sam back. She gave Dean one year before his deal's deadline arrived, warning him that Sam would die instantly if he tried to break his contract.

Season 3
The demon was summoned by Sam in "Bedtime Stories". When he aimed the newly repaired Colt at her, she realized that it wasn't "the original Colt" and deduced that Ruby had been involved in restoring the gun's power.

The demon laughed at Sam's demand that she spare Dean in exchange for her own life. She started playing mind-games with Sam by suggesting that he was only making half-hearted attempts at saving his brother and that Sam was better than Dean and tired of dealing with him.

The demon revealed that Sam killing her wouldn't break Dean's contract, and refused to reveal the identities of higher-ranking demons who could. Much to her shock, the demon was killed when a frustrated Sam suddenly shot her with the Colt for being "a smartass."

Appearance
When disembodied, the demon manifested as a thick cloud of black smoke. The sclera and irises of her human hosts' eyes turned red at will. The pupils remained black but became thin, cat-like slits.

The demon only possessed attractive young brunettes wearing dresses. Of these, one was a black woman wearing a white dress, and three were white women wearing black dresses.

Powers and abilities

 * Teleportation: The demon could be summoned by a human at a crossroad where he buried a box of graveyard dirt, his photograph, yarrow, and a black cat bone. The demon then appeared behind her summoner in moments. In "Crossroad Blues", her host was confused as to how she had appeared at the crossroad, which suggests that it was nowhere close to where she last remembered being.
 * Reality-warping: The demon was able to bestow talent and success upon humans.
 * Healing: The demon cured Evan's wife of cancer. She also restored damage from a fatal knife wound on Sam's spine, although the wound itself remained as a scar.
 * Possession: When summoned, the demon would take over the body of a human to interact with her summoner. When she left her host in "Crossroad Blues", her former host did not remember anything that had happened while she was possessed.
 * Resurrection: The demon brought Sam back to life in "All Hell Breaks Loose - Part 2". However, Azazel suggested that this demon did not bring him back "one hundred percent pure Sam."

Weaknesses

 * Devil's trap: Dean captured the demon by luring her underneath a devil's trap. She was unable to leave the trap on her own power, instead having to rely on Dean breaking the trap by removing one of the boards a portion of the symbol had been painted on.
 * Exorcism: The demon reacted in physical pain to hearing the beginning of an exorcism rite. She was willing to go so far as to break one of her contracts to stop it.
 * The Colt: The demon was killed when Sam shot her between the eyes with a modified version of the Colt.

Trivia

 * The demon's first on-screen actress (Christie Laing) previously appeared in Supernatural as Taylor in "Hook Man".
 * The demon's last actress was Sandra McCoy, who was Jared Padalecki's (Sam's actor's) girlfriend at the time. They later broke up.

Season 2

 * "Crossroad Blues"
 * "All Hell Breaks Loose - Part 2"

Season 3

 * "The Magnificent Seven" (mentioned only)
 * "Bedtime Stories"
 * "Red Sky at Morning" (mentioned only)

Season 4

 * "I Know What You Did Last Summer" (mentioned only)