Mysterious Resurrection: the Spooky Postman

"My name is Lin Feng. When you read this, I will be dead." "Of course, I'm lying to you. I'm still alive for the time being - although it's almost over." "A shadow lives in my body. It helps me avoid evil spirits and is always trying to drag me into eternal darkness." "Interpol wants to recruit me, black marketeers want to dissect me, and that scary postman still insists on delivering a 'letter' to me." "Now, I'm taking the key I snatched from it, looking for an answer that might keep me alive." "Do you think that behind this door, will there be a way of life waiting for me, or will it have been a... Grave that has been prepared for me?"