I Thought It Was the Monster Duke’s Fake Sedative

Synopsis 

“…Why did I have to end up inside this novel?!”

A monster duke has dragon blood flowing through his body, causing him to lose control from time to time. The only way to calm him down is through intimate contact with his destined partner. Lucy is reincarnated into an R-19 dark fantasy novel about him.

The problem is the ending.

The duke never finds his true partner, goes completely berserk, and destroys the entire world.

To make things worse, Lucy is only a minor extra character. Her fate is to be used by the fake partner until all of her holy power is drained, and then she dies.

Accept that fate?

No way!

She tries to escape, but instead ends up right in the arms of the monster duke, who is on the verge of losing control.

“I came to tell you something important. It seems you still haven’t found the person you’re meant to be with.”

“My destined partner?”

“Don’t worry! I’ll help you find your real partner…”

“I thought my partner had already been chosen.”

“Master, that person is fake!”

Lucy stubbornly insists she is right and ends up traveling with the duke just to stay alive.

Her plan is simple:
solve the duke’s rampages, help him find his real partner according to the original story, and then escape safely.

She is confident she can survive this dangerous world just like she survived her previous life.

…Or so she thought.

“I’ve been hurt, Lucy.”

The duke, whom she promised to help find his true partner, smiles at her.

“As always, you’re the only one who can calm me down.”

“…”

“But this time, I think I’ll need a proper purification.”

Why is everything turning out like this?!