First War against the Darkness

First War against the Dakness was a conflict fought prior to the creation of the Universe, 13.8 billion years ago. It resulted in the victory of God and his Archangels, who were, according to him, barely able to seal her away.

History
God existed alongside his older sister, the Darkness. Despite his sister's disagreement, God created many worlds, in order to show her that there could exist other beings besides them, that could, in the end, turn out to be better than them. Refusing God's proposal each time, the Darkness destroyed all that he created.

Seeing her imprisonment as the only solution, God created four Archangels (Michael, Lucifer, Raphael, Gabriel) in order to for them to help him defeat his sister.

After an extended period of time, God and his Archangels barely succeeded in sealing the Darkness away by tricking her, using what would later be known as the Mark of Cain as both lock and key.

Aftermath
After successfully defeating her sister (even if barely), God was able to create the infinte Universe through a very powerful explosion known as the Big Bang, leaving many biological entities to evolve, such as humans.

Trivia

 * This was the very first war ever fought.
 * The fact that God needed four Archangels to barely defeat his sister supports the Darkness' superiority in power.