Silfade Gensoutan

Set in a fictional world named Silfade, from a long, long time ago. The protagonist was incarnate of Rikureru, a goddess-like figure, by means of gathering a spirit from the Sea of Perception, when she witnessed a coming disaster which will wreak havoc upon many lives. Upon incarnation, the protagonist is asked by Rikureru to prevent the disaster, which should occur after fifteen days.