I Became a Villainess in a Deadly Novel

I became the villainess of the novel I was reading. But this novel…

It’s an deadly novel where the empire suddenly collapses
just before the ending!

First I have to live. So I was just trying to go to the next
country but then….

“I waited for 100 years to meet you.”

The man who is the source of the invasion and hides his identity as
Demon King.

Archduke Arvis grabs me with a gaze filled with strong
emotions.

“If I lose you I will probably wipe out this continent that took you
away from me.”

… Why?