Template:Vessel Characters The Darkness often referred as her vessel's name Amara, is a primordial entity who has existed since before the beginning of time, predating both God and Death, who were of similar age. Sometime later after her brother God came into being, he created the Archangels to fight a terrible war against her. Not even the combined power of God and the Archangels could destroy her, so God sealed her away using the Mark of Cain as a lock and key. God knew that he couldn't destroy her outright as she serves as a vital role in the balance of the universe for light cannot exist without darkness. It is shown that if either one of them is lost then the universe would collapse on itself. So to keep her from destroying his creation he thus had her bound.
Whilst the Archangels battled her and thus knew of her existence, she is so ancient and mysterious that the Demons and even the Angels, except for Metatron, didn't believe she existed or was locked away. However, Metatron knew about her and who she was, as he was God's scribe. Both Heaven and Hell thought it to be a "myth" or "scary bedtime story", told to keep others in line.
When Rowena used a spell from the Book of the Damned in order to free Dean Winchester of the Mark (which he gained from Cain to kill Abaddon and had been bearing it since), the Darkness was unleashed once again. When released, her essence gave rise to the Rabids. While on Earth, The Darkness has taken the body of a female baby, Amara. She has also developed an affection for Dean, and is possibly in love with him.