I'm Strong Because I'm Always Fighting, Isn't It Natural?

A piece of human skin that comes from nowhere is floating in the world of immortality. It will choose to possess a person who has died with resentment and has not been around for a long time. By fulfilling their last wish, it can upgrade itself and gain new abilities. Who I am? Where am I? Why do you want to kill me? We are all living hard. Say goodbye to the owner of this body. How come you're still alive after I've tried so hard? How can I close my eyes and find the next person without you dying?