In order to create the Universe, God had to defeat his sister, the Darkness. Their combined strength was barely enough to imprison the Darkness. The lock and key to the Darkness' prison became known as the Mark. God passed the Mark to his most trusted lieutenant, Lucifer. The Mark, however, started corrupting Lucifer, making him more of what he already was.
Ages later, God asked all of his angels to bow down to his new creations humans, which he considered to be his greatest. Lucifer refused, stating that they were flawed, that they were an abomination. Lucifer also attempted to convert his brother Michael (unsuccessfully) and other angels such as Castiel and Uriel to his opposition. Gabriel, meanwhile, left Heaven as he could not bear to witness his family fall apart. Lucifer's defiance caused him to be cast out of Heaven on God's command.
Lucifer continued acting against God's favouritism of humans. He entered the Garden of Eden after Gadreel failed to keep him out, and caused Adam and Eve to eat the Forbidden Fruit. Lucifer infamously created the first demons - first corrupting and twisting the soul of a human named Lilith to make her the very first demon, before going on to turn other human souls into demons such as the Princes of Hell. Lucifer also passed the Mark onto Adam and Eve's firstborn Cain, as part of a deal after the latter discovered Lucifer was grooming Abel to be his "pet"; which led to Cain being turned into a demon by the Mark, and founding the Knights of Hell using demons handpicked by Lucifer.
As punishment for the creation of demons, Lucifer was cast into Hell by Michael on God's orders, and imprisoned in a Cage sealed by God. He would remain trapped until eons later, when the 66 Seals were broken one by one and he was freed from the Cage to begin the Apocalypse.
Casualties and Consequences Edit
- The biggest consequence was the linkage of the Universe and Hell, evil beings able to exist within Earth's plane of existence. The twisting of Lilith and creation of the first demons led to the creation of the Knights of Hell and a giant population of demons, who would come to cause havoc on Earth for eons to come.
- Lucifer's rebellion against God has never once actually been described on the show as constituting a civil war, though it's known he attempted to convince other angels to rebel against God's love of humanity with him, and that he created demons as his own armies and that Lucifer personally acted against God's wishes. In The Third Man, Team Free Will refer to the civil war against Raphael as if such a thing has not happened in a long time if ever before.
- It is unclear when, exactly, either after or before the war, did Lucifer pass the Mark onto Cain.