Introduction 1: I have thought more than once that you are the angel who sneaked out, and I am the devil who fell in love with you at first sight. We put aside all identities, names, genders, prejudices... And embraced each other. But, one day, you will go straight to heaven, and I will go straight to hell, never to see each other again.
Introduction 2: In every place, there is such an urban legend that a company named Zero can travel through various worlds. It can help people who have lost their loved ones resurrect people, but in return, traders have to pay a corresponding price...