My Wife is Terrifying

What should I do if the girl who likes me isn't human? I need help urgently... I'm just an ordinary high school student, nobody cares about me, I've never spoken to a girl, I go to and from school on time every day, I never participate in extracurricular activities. Reincarnated and experiencing the harsh realities of life, Su Wu planned to live a carefree life... using his knowledge from his previous life to make a small fortune, without marriage, a house, or children... and ultimately die alone in his rented room... That was his plan, but sometimes things don't go as planned... When he saw the chopped-up corpse placed in a small coffin, submerged in black water, with strange flowers growing inside... he was terrified and woke up... He thought it was a dream, but a few days later, he was pulled into the scene from his dream... It wasn't a dream, but a real place... and the corpse in the coffin... was also real... "You have awakened the young lady. The engagement is established. You are the chosen one for the ghost marriage. Please go and meet the young lady..." The old man, whose face was half melted away, revealing the white bones beneath the flesh, gave Su Wu a respectful smile, yet appeared incredibly ferocious... "Can I refuse?" Su Wu trembled... "No..."