The Darkness

The Darkness is a primordial entity which has always existed. After the mysterious creation of God, He created the archangels to fight a terrible war against the Darkness. Not even the combined might of God and the archangels could destroy the Darkness, so God succeeded only in sealing it away using the Mark of Cain as a lock and key.

When Rowena used a spell from the Book of the Damned in order to free Dean Winchester of the Mark, the Darkness was unleashed once again.

History
According to Death, before there was any light or God, there was only the Darkness. This entity is credited as a powerful, amoral, destructive force that nearly obliterated anything in its path, causing nothing but chaos. Some time after God and his newly created Archangels battled with The Darkness in a terrible war. He eventually sealed it with a mark that would later be called the Mark of Cain. He then gave the mark to Lucifer, his most valued Lieutenant, to guard. The Mark however showed itself to be a curse; the dark effects of which corrupted Lucifer, leading to a chain of events that would see Lucifer cast out of Heaven. Lucifer then passed on the mark to Cain who then centuries later passed it on to Dean Winchester.

Present Day
The Darkness was eventually freed with the destruction of The Mark of Cain, where it rained down destruction and made a move to consume everything in its path.

Powers & Abilities

 * Immortality - According to Death, the Darkness predates everything, include both God and himself. It is an ageless and invulnerable force that cannot die, and was never truly alive to begin with.
 * Nigh-Omnipotence - While its full powers are unknown, it managed to battle against God and the archangels for an unknown amount of time, and Death was willing to make sure the Mark of Cain, the lock on the Darkness, wasn't broken. Considering the force it took just to fight it back and imprison it, the Darkness is the most powerful evil force in the Supernatural universe.
 * Flight - The Darkness, while disembodied, can fly in a similar manner to demons and angels without a vessel.
 * Invulnerability - Considering its ability to stand against God and His archangels, the Darkness can be assumed to have an immense resilience for physical and supernatural attacks that likely constitutes invincibility.

Weaknesses

 * High-Tier Entities - God, with the combined strength of the archangels, were strong enough to bind the Darkness, and seal it with a lock.
 * The Mark of Cain - The Mark of Cain was the "lock" to the prison that held the Darkness back. As long as one person bore the Mark, the Darkness would remain sealed. With its removal, the Darkness was set free once more.

Appearances

 * Season 10
 * Brother's Keeper

Trivia
•Chaos in Greek/Egyptian mythology, which predated everything and created or from the gods from.
 * The Darkness is similar to many terms and entities found in many creation myths.

•From the quote in Bibical Genesis "And God said let there be light."