Demons

Demons are malevolent spiritual entities created by Lucifer. Created from human souls with endless torture, they're extremely evil. The first-ever demon was Lilith, created by Lucifer. The species as a whole function as the series' primary antagonists and are the most recurring creatures in the series.

Characteristics
Demons are the souls of humans who go to Hell upon death. There are many ways of becoming a demon, from making a deal with a Crossroads Demon, to being a witch, and making a deal with another demon. Their true form appears like long, slender clouds of black smoke. When they possess humans, they enter through their mouths. Often possessed humans physically look exactly the same as they did before possession, but the only noticable changes are the mentality of the possessed human. Often under possession the human begins speaking and acting like the demon would. Upon exorcism the human retains no memory of their time during possession (Unless they have been "awake" during possession, in which case the time of possession is a nightmare for them). Upon possession, the only noticable change of the possessed human is their eyes, which range from deep black to yellow, to pale white and to red, depending on the type of demon possessing them. The possessed humans also gain the powers of whichever demon is possessing them. Unlike angels, whose possession of a human vessel has to be with the vessel's consent, demons forcibly possess humans without any deal at all. Whenever they use their powers, they leave a trace of sulfur in the form of yellow dust. People suffering from stress, fear or panic can be vulnerable to demonic possession. Demons abhor the name of God (which in Latin is Dio or Deus).

Yellow-Eyed Demon:
The one and only yellow-eye demon, Azazel is incredibly powerful. Besides having advanced telekinesis, he can manipulate fire, control dreams, make electrical devices go haywire, and can even possess Reapers. The leader of the demon army, Azazel is subordinate only to Lucifer. He is impervious to holy water conventional defenses against demons or weapons.

White-Eyed Demons:
The most powerful class of demons, white-eyed demons possess numerous powers, the most deadly being that of white light emanation. They are highly dangerous and they rank very highly in the hierarchy of Hell, just under Lucifer. The only known demons of this type are Lilith and Alastair.

Special:
Throughout the course of Supernatural, the Winchester brothers have battled demons that are unique in some way. Examples of these demons include Samhain, the origin of Halloween who is summoned through three blood tests, the Seven Deadly Sins, and the Acheri, demons from Indian mythology that can spread disease.

Crossroad Demons:
Crossroad Demons have red eyes and are shown bargaining with desperate people. They can grant wishes, collect souls, teleport and be summoned by digging a hole in the center of a crossroads and burying a box with a picture of the summoner, some graveyard dirt, and a bone from a black cat. Gifted with immense power, these demons usually possess attractive women to lure men into making deals, although there are exceptions...

Black-Eyed Demons:
The most common demons on the show, black-eyed demons possess little to no power, whether it be super-strength or telekinesis. Effective defenses against these demons include holy water, salt, iron, a devil's trap, ect. Stronger black-eyed demons, such as Meg Masters, are not barred in entering hallowed ground and one demon, Tammi, is shown to have the ability of causing internal bleeding and extensive magical knowledge, such as when she recites a ritual to exorcise Ruby from her body.

Appearances
They have appeared in 56 episodes to date.

Season 1

 * "Pilot" (as a silhouette (later revealed to be Azazel),)


 * "Phantom Traveler" (Introduced).


 * "Scarecrow"


 * "Shadow"


 * "Salvation"


 * "Devil's Trap"

Season 2

 * "In My Time of Dying"


 * "Croatoan"


 * "Born Under A Bad Sign"


 * "All Hell Breaks Loose - Part 1"


 * "All Hell Breaks Loose - Part 2",

Season 3

 * "The Magnificent Seven"
 * "The Kids Are Alright"


 * "Sin City"


 * "Malleus Maleficarum"


 * "Dream A Little Dream Of Me" (in one of Dean's dreams)


 * "Jus In Bello"


 * "Time Is On My Side" (in a flashback)
 * "No Rest For The Wicked"

Season 4

 * "Lazarus Rising"


 * "Are You There, God? It's Me, Dean Winchester"


 * "In The Beginning"


 * "Metamorphosis"


 * "Yellow Fever" (as Dean's hallucination)


 * "I Know What You Did Last Summer"


 * "Heaven and Hell"


 * "Criss Angel Is A Douchebag"


 * "Sex and Violence" (Ruby's Voice)


 * "Death Takes A Holiday"


 * "On The Head Of A Pin"


 * "The Rapture"


 * "When the Levee Breaks"


 * "Lucifer Rising"

Season 5

 * "Sympathy for the Devil"


 * "Good God, Y'all" (as hallucinations created by War)


 * "Free To Be You and Me"


 * "I Believe The Children Are Our Future"


 * "Abandon All Hope..."


 * "Swap Meat"


 * "My Bloody Valentine"


 * "99 Problems"


 * "The Devil You Know"


 * "Two Minutes to Midnight"


 * "Swan Song"

Season 6

 * " Exile On Main Street (as an hallucination created by the Djinn poison)"


 * "Weekend At Bobby's"


 * "Family Matters"


 * "All Dogs Go To Heaven"


 * "Caged Heat"


 * "Mommy Dearest"


 * "The Man Who Would Be King"


 * "Let It Bleed"


 * "The Man Who Knew Too Much"

Season 7

 * "Meet The New Boss"


 * "Slash Fiction"


 * "Season Seven, Time For A Wedding".

Story
Demons were once human, their souls having been corrupted and warped after spending hundreds of years in Hell being tortured and having all of their humanity burnt out of them. They are left as large, black clouds that generate electromagnetic interference and leave behind a sulfurous residue. The first demon was Lilith. She was created by Lucifer, who resented humans for taking his place as the most beloved of God. Lucifer wanted to show how bad humans were, so he tortured a human into becoming a demonic monster. He proceeded to do the same to any human souls he could trick into joining him. However, Lucifer was locked away by his own brother, the Archangel Michael, and Lilith was imprisoned deep within Hell. Thousands of years later, after much searching, Azazel, Lucifer's demonic "son", was able to find the doorway to Lucifer's prison. Lucifer revealed that only Lilith can break the 66 seals keeping him imprisoned, and instructed Azazel to find him "a very special child". Azazel spent the following years feeding his own blood to babies—one being Sam Winchester—as they would then grow up developing demonic abilities, including the ability to kill Lilith and hence free him from his prison, and then be powerful enough to serve as his earthly vessel.

Although an ordinary demon is featured as a villain of the week in the fourth episode of the series, Phantom Traveler, demons do not become actively involved in the show until the introduction of Azazel's "daughter"—possessing a girl named Meg Masters—in the second half of the season. She follows Sam and Dean Winchester, and later unsuccessfully sets a trap for them using their father.

Lower Class Demons

 * Possession
 * Superhuman strength
 * Telepathy
 * Telekinesis
 * Superhuman durablity

Middle Class Demons

 * Teleportation
 * Control of Hellhounds
 * Wish Granting

First Class Demons
Upper Class Demons
 * Pyrokinesis
 * Control of Subconscious
 * Photokinesis
 * Near-invulnerability
 * Angel-banishing powers
 * White light control
 * Ability to withstand exorcisms
 * Control of Hellhounds
 * Invulnerability to the Demon-Killing Knife

Weakness
Salt - Demons are unable to cross a line of salt. Salt can be used to torture demons. It can also be put into shotgun rounds to hurt and knock back demons.

Holy Water - Holy Water burns demons that come into contact with it like acid. Demons like Azazel proved to be immune to Holy Water

Iron - Demons can't touch or cross iron.

Ruby's Knife - The knife originally belonged to Ruby. It will kill a demon that is within a host if the host stabbed in a fatal place. Upper level demons are immune to the killing effects of the knife. One such demon is Alastair.

The Colt - Much like Ruby's Knife it will kill any demon that is shot while within a host if shot in a fatal place.

Bones - If the bones belonging to the demon is burned the demon will be killed much like a vengeful spirit. This can also be used to torture demons. This until recently was believed to be merely a rumor, however Bobby tested this method against a Demon resulting in her death. Crowley may have been aware of this method as he tried to convince Bobby it was "A myth."

Exorcism - Will pull the demon out of its host and send them to hell. Hosts may not survive.

Devil's Trap - A Devil's Trap will hold a demon in place and prevent their escape. The Trap will also prevent a lower level demon from using their powers.

Angel's Touch - An angel can kill a demon by touching them on the forehead with their hand. This power will not work if the demon is too powerful or if the angel is too weak.

Special Children - Sam Winchester developed special abilities almost especially tailored to hurt or kill demons. Due to training from Ruby and ingestion of demon blood he first developed the power to pull demons out of humans. Later the powers advanced to killing demons like the knife or colt. Although unknown it is assumed the other special children may have been able to do this if they survived, trained, and ingested demon blood.

Palo Santo - It is basically the wood version of holy water/salt, when a demon is stabbed the demon screams in pain and the wound smokes. It immobilizes demons long enough for exorcism.

Hallowed Ground - Some demons (lower-level ones) are unable to enter hallowed ground.