The Time I Became A Soul Girl.

Seventeen-year-old Yuu Toriyama, a stand-offish teenager who couldn't connect with anyone but her mother, had spoken to a bird; a bird who claimed it was God itself. It told her that in seven days, demons will emerge, and ravish Earth, assigning her and four others with the task of being a "soul girl."  She didn't get a choice—she had no say in the matter. This bird, this so called "God" had already decided her fate—her fate being to risk her very life for humanity itself.