Demon Charmer

You finds yourself accidentally involved with a demon who turns you into a demon and sends you to the past. In that era, you discovers that you resemble a certain character from a popular series, 'Demon Slayer.' Besides, you encounter other characters from that same series. Is it a hallucination or is it real, and these characters really exist?. Even with doubts you will try to survive at all costs, with the possibility to choose a path of good or one of evil.