The Perfect Plan to Avoid the Death Ending

I’ve been reincarnated as Sienna Winter, a minor villainess with a terminal illness in a novel. My only goal is simple: To survive without dying! But then… “I am Helares Eckbert. You are the one who awakened me.” “…Excuse me? Who are you?” “Nice to meet you, master.” I accidentally awakened a sealed demon. And as if that wasn’t enough, I got tricked into a fraudulent contract? “This contract is valid until you die.” “…Pardon?” “It’s a lifetime contract, you naïve little lady.” “…But I’m terminally ill?” Can I really survive in this situation…?