Gabriel
There are some beings in this world that are impossible. They are beyond the mind's idea of beauty and though they know it, they only carry it as a sash, never a badge. Those that are strong realize that they are chosen, and have no choices whether they are noticed or not. Those that are weak follow, chasing just the wisps of such a shadow to feel great. These people are without failings because the faults are unnoticed. They are called Leaders, Prophets, Blessed, and even sometimes gods. They exist whether they are noticed or not. And when this greatness is twisted, the results are horrific. Every great leader can turn into a tyrant, just as every prophet can turn into occultist. The strong and the weak follow the same but what could have been joy is now just rage. This is how wars are started, and worse still, how they are ended. This is what he did to the great leagues of the angels. Rather than continuing to be an excellent leader of a formidable legion, he handed them over to their enemy. This meant death to every angel who did not stand beside their leader's choice. Worse still, this meant that every angel who stayed fought for their enemy. And their leader? His choice was so respected by the demons that he became their leader as well. Even the angel Lucifer sighed and shook his head at the betrayal, for his was a decision he did not make himself. This leader of the angels, this traitor of his kind, was simply known as Gabriel. Under his rule of demons and angels there was nothing left to protect the humans. They angels charged to save the humans were forced to merely watch without action, or for those who were cunning, move hands to keep the humans safe. The demons moved within the orders of Gabriel which were few and gave much leave. This is not where it started, but where many of the troubles began. So it has been known to both demons and angels alike, no matter how they tell it.