Demon Summoning

This refers to a set of rituals that summon demons. There are several summoning rituals and they vary according to the type of demon being summoned.

Generally, summoning a demon would require several ingredients, fire, whether by form of candles or by igniting the ingredients, sigils, and most of the time, a Latin incantation. Although summoning a demon requires spellwork, and are usually performed by witches to draw power from demonic forces, demon summoning rituals can be performed by ordinary people.

Crossroad Demons
This ritual specifically summons crossroad demons. This is usually done to strike a deal or, in the case of hunters, to retract or negotiate other deals or to capture a demon.

Ingredients
This ritual requires a crossroad and burying a box in the middle of it. The box must contain a picture of the mortal wishing to make a deal, graveyard dirt, and a bone from a black cat or milk from a black cow. The crossroad, sometimes must have Yarrow flowers being planted at the crossroads. It helps in the ritual, though appears to not be a necessary component.

Incantation
Unlike most demon summoning rituals, summoning crossroad demons do not require incantations--with the exception being the King of Crossroads, Crowley, who is summoned with a different ritual altogether.

However, in Captives when summoning the crossroad demon possessing Snooki, Sam uses an incantation which later the incantation also used for summoning various Crossroads in further episodes. The Incantation is in Latin:
 * Daemon, esto subjecto voluntati meae.

Any Demon
This ritual summons any demon that answers the invocation. This was performed by a young witch named Trevor.

Ingredients
It requires several lit candles, a bowl of mixed ingredients atop a Baphomet symbol, which is a goat head inside a pentagram.

Incantation
The incantation was rather short and only one line was clearly audible.
 * Ad ligandum eos pariter eos coram me.

Exorcised Demon
This ritual summons a demon that has previously been exorcised. This ritual was described by a white witch to be the strongest summoning ritual she has ever seen, because the spell can even summon a demon that was cast to the deepest side of Hell.

Ingredients
It required a bowl of burning coal atop a sigil, the blood of the exorcist, the heart of a dog, and an incantation.

Incantation
The incantation is in Latin, like most incantations to summon demons. Speaking the incantation will cause the earth in surrounding vicinity to violently shake, until the demon is able to manifest in a nearest, suitable vessel.

The incantation, actually, is long enough, but unfortunately, due violently earthshaking sound effect, the incantation is gibberish and hard enough to hear. Only the first part of the incantation is clearly audible:
 * Te invoco apro fundus inferni...

Specific Demons
It is possible to summon specific demons provided the summoner knows the corresponding ritual.

Azazel
Azazel was the first demon shown to be summoned with a ritual, and by extension, a ritual exclusive to him.

Ingredients
The ritual to summon Azazel required acacia, oil of Abrameli, lit candles positioned atop the Sigil of Azazel, also known as the Sigil of Saturn.

Incantation
The summoner must recite an incantation in Latin:
 * Attenrobendum eos, ad consiendrum, ad ligandum eos, potiter et solvendum, et ad, congregontum eos, 'coram me.

Crowley
Crowley could be summoned through a ritual specific to him, although he could choose to appear with just a simple crossroad demon summoning if he was interested with the deal being made.

Ingredients
Summoning Crowley required several ingredients. Interestingly, the ritual requires the use of a sigil very similar to Azazel's. Lit candles must also be aligned with the sigil. A bowl of several mixed ingredients with the blood of a summoner is also required. The bowl must then be set aflame by throwing a matchstick into it.

Incantation

 * ...Et ad congregandum...eos coram me.

Variation
Dean using another variation summoning ritual to summon Crowley. It requires a sigil that very different than Bobby's used. A sigil (which constituted by triangle enclosed by circle) had to be drawn and three lit candles had to be aligned with or around the sigil in each tip of the triangle.

The ritual also required various ingredients. The ingredients seem very complex, which consisted by various dried herbs, nuts, and preserved fruits. The ingredients must be put in the bowl which placed atop the sigil, properly mixed, and set aflame. There were no form of any blood offering nor incantation required to perform this summoning spell. Sam later in the end of the episode, later using the same spell to summoned Crowley again. However, its unknown, he mixed the spell from the scratch again, or he simply used the remains of Dean's summoning attempt.

In Brother's Keeper, Castiel used this variation to summon Crowley. However, in this occasion, he performed it on a crossroad like summoning common-level Crosroads.

Ruby
Sam uses a summoning ritual to call upon Ruby in No Rest for the Wicked. This ritual bears many similarities with the ritual John used to summon Azazel. However, the Latin incantation Sam uses is slightly different from John's.
 * Ad constringendum, ad ligandum eos pariter et solvendum: Et ad congregandum eos coram me.

The sigil Sam draws differs greatly from the one John used, depicting a circle within a single closed triangle, with three additional symbols drawn inside each triangle corner. The placement of the bowl of ingredients also changes; it is placed in the center of the circle. Only three lit candles are used and they are positioned on the tip of the triangle corners.

Samhain
Samhain could only be summoned once every six hundred years. The exact details of how he is summoned were not revealed. However, unlike all other demons, the ritual to summon Samhain is more complex than lesser demons, this is because Samhain was incredibly more powerful than a regular demon. His arrival was carefully prepared by two extremely powerful witches who were able to hide themselves effectively against angels. Summoning him also broke one of the 66 Seals.

The ritual to summoning must be performed by two powerful witches. It required three blood sacrifices to performed over three days, the last one on the final day of the Harvest, Halloween. Blood from the final sacrifice must then be collected in a chalice, where one of the witches will recite an Old Celtic incantation (which very hard to hear) at a black altar with pentagram, 5 black candles, goat skull, an unidentified grey rock/ore with a hexagon motif inscribed with a metal spike protrusion protruding in its middle, a chalice filled by blood which collected before in third sacrifice, and a Celtic cross made from stone. Once done, the earth will crack allowing Samhain to take possession of a meatsuit.

Daeva
This shadow demon could be summoned by the use of an altar with a Zoroastrian symbol drawn in blood, candles, talismans, a card depicting the same symbol, among other things. Keeping the altar intact is important to maintain control over it.

Acheri
This demon was summoned by the special child Ava simply through the power of her will and mind.

The Heart of the Dragon (Non-canon)
In Supernatural: Heart of the Dragon, Albert Chao, one of archnemesis of The Campbell Family and The Winchester Family, able to summon the spirit. In the first and second attempt (when encountered by the Campbells and Winchesters respectively), he used certain invocation to summon it. The form of the invocation is not revealed.

In third and last attempt, assisted by witch Moondoggy Verlander, he was no longer using the invocation anymore (possibly due to John Winchester attempt in second attempt). Instead, he used a powerful demon summoning ritual to summon The Heart of the Dragon. The summoning spell is unique, becuase it should be performed on the night of the new moon, or otherwise it will fail. The ritual used a black altar consisted of many ingredients that should be placed atop the table. To perform the summoning, a spell (possibly Chinese, but written in latin alphabet in paper, since Moondoggy cannot recognized it but well-known by Albert) must be recited. Once the spell recited, the black altar will flashed and burned along with the ingredients to pile of ash, and the spirit will summoned immediately.

Appearances

 * Season 1
 * Shadow
 * Season 2
 * In My Time of Dying
 * Crossroad Blues
 * All Hell Breaks Loose - Part 1
 * All Hell Breaks Loose - Part 2
 * Season 3
 * Bedtime Stories
 * No Rest For The Wicked
 * Season 4
 * It's the Great Pumpkin, Sam Winchester
 * I Know What You Did Last Summer
 * Season 5
 * Abandon All Hope...
 * Swap Meat
 * Season 6
 * Weekend At Bobby's
 * Season 7
 * Meet The New Boss
 * Repo Man
 * There Will Be Blood
 * Season 8
 * Taxi Driver
 * Season 9
 * Captives
 * Do You Believe In Miracles?
 * Season 10
 * Soul Survivor (flashback)​
 * Brother's Keeper