The Legend of the Holy and the Damned:
Dark Angel-Vampire [man]
Angel-Heavenly Warrior [woman]
Twin Half Breed Abominations [women]
Long ago, the Angel, Joseph was forced from Heaven many Millennia ago. Along with a group of about fifty other Angels. They had been his Followers; the ones who had disagreed with God's teachings. They had been among the Rebellion. War had broken out and when it was finished the Rebellion had lost.
The punishment for the crime was banishment to Earth. To live amongst the humans. But in doing so God's actions had an unforeseen consequence. The group of Angels changed to reflect their inner torment. They, then reflected the opposite of what they once were.
They became known as Dark Angels. The counter parts to the Angels of Heaven. Some of them faded into the crowds. Others mated with mortal women. To create children that were half mortal/half Dark Angel.
The children had the power and the souls of a Dark Angel, but the spirits and the minds of man. They were normal humans until their seventeenth birthday. Where the Dark Angel half of themselves would start to assert itself. Angel and human nature don't always tend to in many cases mix well. During the week after their birthdays many fell victim to madness.
This being the case, God felt that the children were the Dark Angels's way of mocking him. So he sent Heavenly Warrior Angels down to wage war with the Dark Angels. As the legend dictates, there will be born a set of twin girls who are half Angel and half Dark Angel. They will have the power to tip the scale between the light and the dark...