Before everything else, when God first came into creation, he created a companion. This companion would be His equal, for they were created from half of God's own Grace. They existed together for many years, happy to simply have each other, until one day, God became curious about his powers. He started to actively use them, and from it was Heaven.
God's Companion was amazed by what God had created. Seeing what had come from His power, His Companion decided to attempt to create something for Him. From their attempt came a physical plain to stand counterpart to the metaphysical plain God had created. Together they looked upon this physical plain, and called it Earth.
After realizing what they could create, they started creating many things. God created trees, His Companion created animals. Anything one would create the other would create something to go with it. Finally, both plains were filled with wondrous creations that all had purpose to the whole, Creation.
During a period of time that His Companion was creating far off galaxies to decorate the night sky, God had an idea. Since practically the very beginning, they had been alone together. There had never been anyone else. So God wondered if he would be able to create others to share in their happiness.
He started by trying to create beings that would be created from the cosmos, instead of His own Grace. They turned out to be a failure. Because they had not been created from Him, they weren't self-sustaining. They needed to constantly intake more of the cosmos. They were destroying everything He and His Companion had created.
With the inspiration to get rid of His first attempt at others to enjoy Creation, He created metaphysical beings modelled after His Companion, from only a miniscule amount of His Grace. He named these beings Archangels, and set them against the other creations, that he named Leviathans.
After a lengthy battle, the archangels defeated the Leviathans, and He created an eternal place to hold them, and others such as them. He named this place Purgatory. He them bestowed upon the archangels names. The first, was named Michael, and then Lucifer, Raphael, and finally, Gabriel.
He looked at His newest creations, and bore witness as they swore to serve Him, for He had created them from the purpose to enact His will, and they were thus bound to it. Having had His Companion with Him for so long, He knew this was wrong. He started nurturing them, to try to teach them to make their own choices. He even created them younger, less powerful siblings to help them to understand the act of making choices for others. He put so much of Himself into this task, that He forgot about His Companion.
When His Companion returned from his quest to add beauty to the sky, he found poor imitations of himself roaming everywhere. He hid himself from them and looked upon what they were doing. He was horrified to discover, through overhearing conversations, that they did not know of him. He had been forgotten, after so long together with Him.
He decided to wait, and watch what would become. He stood by, and watched as humans were created, and Lucifer rebelled. Finally, when He left the angels as He had left behind His Companion, he decided he could not watch anymore. He worked his power, and placed a block on his Grace, and placed himself into the human soul cycle. His last thought, before his memories were blocked, was such.
I take upon myself the name of Samael, for this name means Venom of God, and I myself feel venomous after being forgotten by Him. May He one day remember me, and realize His mistake.
And so, Samael forgot, and after many years, was born an infant, and given the name Samuel Winchester.