It had started five thousand years ago.
A girl was born.
And the first thing she saw was her mother being murdered in front of her.
She screamed; her screams reached the heavens but no one came to her rescue: not even the god who sired her. She cursed the world- she cursed the land, she cursed the people and seeing her desperation and rage, a demon responded. Not the gods, nor the angels: but a demon. A demon born from the sins of mankind- the true demon. A demon that came from another world.
The girl- though she couldn't even move- offered the demon her life in exchange for revenge.
The demon obliged and formed a pact- a pact that would last five thousand years. At the time, the girl did not understand that perhaps innocent people; and maybe people that aided her mother escape; and wished her well, were also part of the country. But it was too late and the whole country was wiped.