The Wind Is Cold and the Rain Is Falling

As soon as he opened his eyes, he saw a blank space. The unknown creature in the shape of slime claimed to be the system and told him in a mechanical voice that he needed to complete many stories here before he could go back. However, his memory was too damaged to remember many things. Only by following the instructions of the system could he recover his memory bit by bit and go back. And after he went through one story after another, he discovered a clue. The protagonist of all the stories was the same person. As his memory continued to recover, he also discovered his own situation...