Raina had no idea of who she was or where she came from, but the four seraphs that captured/rescued her said she was the vessel—and they were there to supply the seed.
When all of the elements came together they would produce a force powerful enough to save the world. She was the light—the giver of life—the flame of creation. They were Earth, Wind, Fire and Water.

She was pretty sure they were nuts—beautiful but looney.

On the other hand, it transpired that they could do some pretty amazing shit ....