Names this 'character' is known by both in fandom and canon:
- The Demon (all Winchesters refer to it thus in Season 1)
- The Yellow-Eyed Demon (Dean refers to it thus in Season 2)
- Celine Demon (a nickname used by the fans. See below for an etymology of this nickname)
- In a draft script for 2.02, Dean refers to it as the Big Bad.
- 1.01 Pilot appears as figure next to Sam's crib
- 1.11 Scarecrow Meg Masters communicates with him through the goblet of blood
- 1.16 Shadow Meg Masters communicates with him through the goblet of blood
- 1.21 Salvation appears as figure next to Rosie's crib
- 1.22 Devil's Trap possesses John Winchester
- 2.01 In My Time Of Dying appears to John Winchester as a janitor in the hospital basement
- 2.09 Croatoan Duane Tanner communicates with him through the goblet of blood
- 2.21 All Hell Breaks Loose: Part One appears in a dream to Sam
- 2.22 All Hell Breaks Loose: Part Two uses Jake Talley to enter the devil's trap built by Samuel Colt. He is killed by Dean with the Colt, with some help from John Winchester.
- 1.22 Devil's Trap played by Jeffrey Dean Morgan
- 2.01 In My Time Of Dying played by Fredric Lehne
- 2.21 All Hell Breaks Loose: Part One played by Fredric Lehne
- 2.22 All Hell Breaks Loose: Part Two played by Fredric Lehne
- The Demon attacks families on the night the baby is exactly 6 months old. (Jess is the exception to this rule - Sam is 22 & 6 months old.) However, the family of Ansem Weems (Webber) were never attacked, thus destroying the Winchesters' hope that they would be able to use this as a marker to track those for whom the Demon has "plans".
- A week prior to the attack, the geographical area has cattle deaths, electrical storms and temperature fluctuations.
- It makes clocks stop, and electical devices go haywire.
- It is impervious to Holy Water
- Following what appears to be a surge of activity around the time Mary died (Max's mother was also killed around this time), the Demon was dormant until late 2005.
- It has yellow eyes (iris and pupil).
- It possesses human hosts, but can exist in a disembodied form also.
- Impervious to the salt barrier.
- It is vulnerable to the Colt.
- In 2.21 All Hell Breaks Loose: Part One it is revealed the Demon has been bringing the Psykids to Cold Oak and pitting them against each other. The strongest one will be selected as the leader of his army.
- In 2.21 All Hell Breaks Loose: Part One the Demon tells Sam he killed Jessica to force Sam back into hunting so he would be better trained. In a vision fo the past he reveals that on the night when Mary died, he feed his own blood to baby Sam, and that Mary recognized the Demon.
The Yellow-Eyed Demon chose a group of Special Children to take part in war against humanity.
- Andrew (Andy) Gallagher
- Ansem Weems (Webber)
- Ava Wilson
- Jake Talley
- Max Miller
- Sam Winchester
- Scott Carey
Relationship with Sam Winchester
- A link between Sam’s powers and the YED is first suspected by the boys in Nightmare, when Sam discovers that Max Miller’s mother dies the same way Mary Winchester did.
Sam: I mean, either telekinesis or premonitions, we both had abilities, you know? Maybe it was after us for some reason.
- In Devil’s Trap, the YED reveals that he killed Mary and Jess because they got in the way of his plans…
YED: My plans for you, Sammy. You... and all the children like you.
- In 2.01 In My Time Of Dying we find out that John knows “the truth” about Sam and the other children like him.
- In Simon Said Sam meets two other people with powers, Andy and his evil twin Ansem. Ansem reveals that a man “with yellow eyes” has visited in his dreams and revealed he has big plans for the Psykids.
- In Simon Said Sam and Dean also discover that not all Psykids had their mother die in a fire when they were six months old.
- In Croatoan, Sam is infected with a demon virus. This is revealed to have been an experiement enginnered by the YED, when Duane Tanner contacts him on a blood goblet to report:
"I don't think any more tests will be necessary... The Winchester boy, definitely immune as expected."
- In Hunted Dean reveals that before he died John told Dean that he would have to save Sam, and that if he couldn’t do that he might have to kill him.
- In 2.21 All Hell Breaks Loose: Part One The Yellow-Eyed Demon appears to Sam in a dream, and explains that his plan is for the children with special powers to fight amongst themselves until the strongest is left to lead the Demon’s army. He tells Sam, with his leadership qualities and hunter training, is his favorite.
- In the same dream, YED admits to killing Jessica so Sam would go back to hunting. He then shows Sam a vision of what happened the night Mary died. Sam sees that YED fed drops of his blood to baby Sam, and that Mary knew the Demon. Sam does not tell Dean about this.
The Demon's Children
- Include: Meg (S1), Tom (S1), Duane (S2), Sam when possessed by the same demon who possessed Meg(S2).
- Meg refers to YED as "Father" in 1.11 Scarecrow (episode).
- In 1.22 Devil's Trap, YED refers to Meg as his daughter, and Tom as his son.
- They communicate with YED using the Goblet of blood
- The Demon can possess human hosts, and is able to animate the human body they are possessing even if the body sustains mortal injury.
- Eyes turn entirely black during possession, though this can seemingly be turned on and off.
- They are impervious to hallowed ground ("that may work in the minor league, but not with me" - Meg, Salvation), but not to Holy Water.
- They can be exorcised and thus the Demon returned to Hell.
- Possession can occur by physical contact.
- Restricted by the salt barrier.
- Vulnerable only to the Colt.
Etymology of the "Celine Demon" nickname
The term Celine Demon was coined on the TWOP boards on September 14, 2005, in a discussion after the airing of the 1.01 Pilot (episode) and refers to the demon who killed the Winchester brothers' mother Mary Winchester.
It derived from a misreading of the words Ceiling Demon as Celine Dion (Canadian popsinger) by TWOP-user thinkcwik. The singer's name and the nickname for the demon were meshed and the new term stuck.