The False Saintess of Mt. Goodbye

Have you heard of the lovely lady that lives in the mountains?
As bright as day and calm as night?
Have you heard her voice and basked in her light?

Well I have and I'll tell you true...
She'll draw you in... then kill you...
She'll giggle and act all shy...
For she is the False Saintess of Mt. Goodbye.
.................................

Six months after dying and finding herself in a new world, our Main Character finds herself the enemy of humanity after killing an animal that was considered a symbol of strength to all humans even though... it was in fact a spy for the demonic race that seeks to destroy them?

Finally, after giving into fate, she shows them how evil and much of an enemy of humanity she can be.