Mark of Cain

The Mark of Cain was the seal created in order to lock away The Darkness. God gave the Mark to Lucifer, who in turn passed it onto Cain the source of The First Blade's power. It is one half of the weapon that Cain used against the rest of the Knights of Hell. Cain later transferred the Mark to Dean, so that the hunter could kill Abaddon. It was destroyed when Rowena cast a spell from the Book of the Damned.

Overview
According to Death, before humanity and Earth existed, there was the Darkness. God and His archangels defeated the Darkness in a terrible war and after He locked it away, God created the Mark as a lock for the Darkness. He gave the Mark to Lucifer and it corrupted him into being jealous towards humanity. He passed it onto Cain and it corrupted him too. If the Mark is removed without being passed on, the Darkness will be released once more.

When Dean used the First Blade for the first time, he felt a murderous rage that did not dissipate after he killed a victim with it. It later gave him immunity to Abaddon's powers and telekinesis and have a telekinetic control of the blade, all with great concentration, allowing him to overcome and kill her. After killing Abaddon, this rage caused him to mutilate her corpse. He also displayed superhuman strength while fighting a vampire. Dean later showed precognition, receiving a nightmare about a slaughter he would later commit under the Mark's influence. When a human with the Mark refuses to give into its rage, it seems to keep them from being able to access its other abilities as when Dean fought Cain and didn't give into the Mark's rage, he displayed no extraordinary abilities which Cain noted. However, though mostly due to the devil's trap Cain was confined in that bound most of his powers, Dean proved capable of defeating Cain even without the Mark's abilities while Cain with the Mark's abilities couldn't defeat him.



When the bearer of the Mark receives a mortal wound that would kill them, the Mark transforms their soul into a Knight of Hell, so that it can live on, and never perish. It is also revealed that if the bearer does not satisfy the mark, by killing, it will slowly but steadily turn them into a demon (presumably to make them willing to kill). Castiel explains that the grip of the mark affects the bearer on more than just a purely physical level, and that cutting it off or even burning it off wouldn't work and it would require a source of great power. He even stated that it reaches back to the time of creation itself and that it predates the lore. According to Metatron, there is a way to remove it and it requires the First Blade to work. Conversely, Cain himself claims there is no cure. Metatron later admitted about lying about knowing how to remove the Mark though Rowena claimed it is simply a curse, the oldest curse in existence but even she doesn't know how to remove it.

It is later believed that the Book of the Damned contains a spell to remove the Mark of Cain from a human and fully cure its effects, but it comes at a price: If not properly handled, it will do far more harm than good. Rowena is eventually able to use the spell to remove the Mark from Dean's arm, but it released the Darkness as Death warned.

Effects of the Mark
The Mark imbues its bearer with several powers as well as psycho-supernatural burdens which eat away at the bearer's character.
 * Super Strength - The Mark grants the bearer enough augmented strength to overpower a lower vampire and shrug out of a lesser angel's hold. Dean was able to easily massacre a whole room full of grown, strong men, and emerge seemingly unharmed. Dean was able to effortlessly hoist Abaddon into the air while stabbing her with the Blade. Dean later effortlessly breaks free of ropes tying him to a chair and leather restraints. He also proves strong enough to beat Castiel, a Seraphim with ease. However, he was unable to defeat Metatron when he was in possession of the angel tablet.
 * Murderous Rage - The Mark affects the bearer to where they constantly must kill something, if they don't they'll eventually die as pointed out by Crowley. However, as demonstrated by Cain, this could be fought and Sam suggests that the bearer must want to at a conscious level for it to work. Metatron states that each time the bearer gives into the Mark's rage, they fall more and more under its power. After giving in to its power once more, Cain felt that it was better to let the Mark control his actions and not fight it. After Charlie Bradbury was murdered by Eldon Frankenstein, the rage caused Dean to slaughter his entire family and even kill an innocent boy. He also nearly killed Castiel under its control but stopped himself in the end.
 * Telekinesis - The Mark grants the bearer the ability to summon the Blade to the hand that calls it.
 * Resurrection - The Mark, if the wearer dies, will resurrect the bearer back to life as a demon, more specifically a Knight of Hell. This can be reversed through the Demon Curing Ritual though the wielder will still retain the Mark even after being rendered human again. However, Cain indicated that if one wielder of the Mark killed the other with the First Blade they wouldn't come back as he seemed to think his killing Dean would be permanent. He also seemed to believe Dean killing him would be permanent too.
 * Immunity - The Mark allows the wearer immunity to demonic powers, as shown by Dean resisting Abaddon's telekinesis. It also granted Dean great resistance to the Demon Curing Ritual, causing him to retain demonic mannerisms long into the ritual even when he was made human enough to be immune to a devil's trap. However, the Mark did not make him completely immune and he was eventually cured. It doesn't typically grant immunity to magic, as the Transfiguration Spell still affected Dean. However, if the spell used is able to kill the bearer of the mark, it will shield him/her from it as to keep the host alive. As seen, the mark made Dean immune to a spell Rowena cast that should have ripped his body apart.
 * Super stamina - The Mark greatly enhances the bearers stamina. Dean was able to go without sleep and food for several days with no ill effects.
 * Precognition - Dean had a nightmare that showed him in a room having slaughtered a group of men. It later came true.

Appearances

 * Season 9
 * First Born 
 * Sharp Teeth
 * The Purge (Mentioned only)
 * Blade Runners
 * Mother's Little Helper (Flashbacks/Mentioned)
 * Meta Fiction
 * King of the Damned
 * Stairway To Heaven
 * Do You Believe In Miracles?
 * Season 10
 * Soul Survivor
 * Fan Fiction
 * Ask Jeeves
 * Girls, Girls, Girls
 * Hibbing 911
 * The Things We Left Behind
 * The Hunter Games
 * About a Boy
 * The Executioner's Song
 * Inside Man
 * Book of the Damned
 * The Werther Project
 * Dark Dynasty
 * The Prisoner
 * My Brother's Keeper