Ghost and Joker: A thing to do for you

A visual novel included in the Story Me app. One day you wake up as a ghost… "Joker", a girl dressed in black, a "Grim reaper," says you "Must help those who are living", if you want to regain your missing body and lost memory. You are approaching extinction, mysteries are arising everywhere, and the living are suffering... Can you resurrect yourself and reach the truth of this story?