Declare your life, and be assigned the campaign you must follow.
If you choose the Light as an Angel, you will experience the struggle of the Armies of Heaven, as you progress from a simple infantry soldier to finally become one of the chosen, the Champion of Angels.
Choose the Dark Side and become a minion of evil, learning to use all means to expand a reign of chaos and malice to the Afterworld. Slay angels and subjugate the souls of dead men so they all kneel for you, and become slaves of the Lord of Darkness.
If you believe neither light nor darkness will ever bring the war to an end, why not join the Souls of Purgatory, the army of men dead long ago, who fight for their freedom and a Kingdom of Men beyond the shores of death?