Cain

Cain is a retired demon known as the Father of Murder who used to train the Knights of Hell.

Human Life
Cain was the older brother of Abel. Although it was originally and commonly thought that Cain was jealous of his brother Abel, and killed hi out of contempt, Cain later revealed that Abel was in fact talking to Lucifer, not God as formerly thought. In an effort to protect his brother from corruption, Cain offered a deal. Cain offered himself to Lucifer so that Abel would go to Heaven instead. Lucifer agreed, on the condition that Cain himself would send his brother to Heaven. Thus, Abel was struck down by Cain using the First Blade.

Life as a Demon
Because of killing his brother, Cain became a demon, and was considered to be the most terrible demon to ever walk the earth before suddenly vanishing. This act of killing between brothers would set the precedent of their descendants being the vessels of Michael and Lucifer, and thus, again require a brother killing a brother during the Apocalypse.

Cain was the mentor of the Knights of Hell. He created the entire order with his bare hands, and also killed all but one with the First Blade.

In Jasper Springs, Mississipi, Abaddon, the last remaining Knight, possessed Cain's wife Colette, in an attempt to coerce Cain to return to his work as the leader of the Knights. When Cain declined, Abaddon killed Colette. It was during then Cain made a promise to Colette that he would retire from his work as a demon.

During Cain's disappearance, all other demons thought or hoped he was dead. Crowley described him to be "the best at being the worst".

21st Century
Cain lived life as a bee collector in Missouri. After being convinced by Dean to live up to his reputation, and realizing that the hunter> was similar to the demon, Cain decided to transfer the Mark of Cain to Dean. He then teleported Dean and Crowley to safety after making Dean promise to return and kill him after killing Abaddon. He then took on an entire army of demons single-handedly.

Personality
Cain is tired of the violence of demon life. He gave up killing demons for his wife. After his wife's kidnapping by Abaddon, he massacred the Knights of Hell in his attempt to get her back. When Dean came to him for help with getting the First Blade, Cain returned to his old ways, but apparently tired of life and what he was going to do, he asked Dean to kill him once Abaddon was dead, showing a death wish. When human, he was also loyal to his brother Abel to the point that he sacrificed himself to ensure Abel a place in Heaven.

Powers and Abilities
Cain was an extremely powerful demon. He could kill other demons with a mere touch. He could even prevent Crowley, the King of Hell and a powerful demon himself, from escaping and speaking just by a simple gesture. His strength was also shown when he killed an army of demons singlehandedly.
 * Immortality - Cain is at least 10,000 years old.
 * Demonic Possession - He possesses humans to exist on Earth.
 * Super Strength - Being the original Knight of Hell, Cain is considerably stronger than lesser demons, lifting one off his feet with one hand.
 * Telekinesis - He could move objects with his mind.
 * Teleportation - He teleported from across a field to beside Dean and Crowley and then to Collette's grave and back.
 * CainKillingTouch.PNGDemonic Smiting - He can kill demons with a touch similar to angels. Except in Cain's case, the color is red rather than bright white light.
 * Immunity - Cain is completely immune to the demon killing knife. Only the First Blade could kill him.
 * Invulnerability - Cain is invulnerable to normal and mortal harm.
 * Apporting - Cain was able to teleport Dean and Crowley outside with a touch.
 * Power Negation - Cain is able to negate abilites of weaker beings as he did with Crowley.

Trivia

 * The set for Cain's home is the same as Bobby's.
 * Cain is similar to Dean in many ways. Both of them wanted to keep their younger brothers from being corrupted. They also took extreme measures to make sure their brothers were saved, regardless of the rest of the consequences. Cain also remarked that Dean's bravery was very much like his. Finally, they both carried the same bloodline that could host the archangels.

Appearances

 * Season 5
 * The Song Remains the Same  (Mentioned only)
 * Season 6
 * The Man Who Would Be King  (Flashback only)
 * Season 9
 * First Born  (Mentioned only)