Devil Lady

Princess Marian Eve Godarm—the unwanted one.
After the death of her mother, Empress Eve, and her younger brother Persian in a tragic accident, Marian found herself transformed into an unwelcome presence within the imperial palace—displaced by the Wynkar faction that had claimed position at the Emperor's side.
Eventually, she faced the prospect of being sold off as little more than a vessel for producing noble bloodlines.
"Who would you wish to marry?"
The Emperor, in a final gesture of fatherly benevolence, granted her the privilege of choosing her own husband.
One choice rose to the surface of her mind.
Her childhood companion of many years, the man she had loved in silence.
David Cromwell.
But the tender soul he had been in years past had long since vanished.
"They say you've come because you're unwell. Where exactly... do you mean to say you're in pain?"
"My head aches constantly. My knee is injured as well."
"I see."
Some incident had caused him to close his heart to her.
Marian had returned to the Cromwell estate to convalesce—ostensibly recovering from her stay at the convent where she had been praying for the Emperor's health—when she inadvertently ingested poison, placed there by someone's design.
The realization settled upon her that even the Cromwell ducal castle was not safe ground. Desperate to convey this truth to David by any means necessary, she entered his private study—
—and there, in that sealed chamber, she came face to face with a forbidden text that should not exist in this world...