Juuyoku no Jousai, the Fortress of Carnal Lust [v2.0] [Fullfrap]

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!

NotAnAlien thanks for the link