I Have the Villainess's Script, Yet I'm the Savior?

Here's what happened: after I was accused of impersonating the noble young master’s lifesaver and poisoning his real lifesaver, his fiancée, I learned that I had also once forced a highly skilled disciple of an immortal sect to marry me in exchange for rescuing my childhood friend, another disciple of that sect.

And someone like me is actually tasked with saving the world and defeating the Great Demon King?!

Am I not already demon enough???

[This blurb is just a placeholder for now.]

Theme: With great power comes great responsibility