Hell Demon Slayer

This is a world where demons are rampant. Chen Feng brought a golden finger with him after traveling through time, but he didn't expect that this would be the beginning of his gradual descent into hell. If you want to become stronger and survive, you must slay demons. To slay demons, you must use the power of hell. And every time you use the power of hell, your body will become more and more like a hell ghost... Who am I? Is it a human being, a ghost, or... Is this world real?