Juuyoku no Jousai

The story starts as an adventurer sneaking into an ancient castle in search of treasure. In the ancient castle, she is violated by magical beasts, and enters a deep sleep. When she awakens, she finds her soul has been separated from her body. If she can't find a way to remove the beast's curse, her spirit will diminish, and eventually disappear. Time is of the essence, she has to hurry. She must fight for her life!