Between Madman and Demon Slayer: My Dual Identity

A young man saw ghosts and immortals, but was sent to a mental hospital? The doctor said I was terminally ill, and the medical records were filled with "conjectures." The roar of the fierce ghost in red is still in my ears, and the grace of the fairy's sword is unforgettable. Until a glass of water splashed on the consultation table, and a ray of golden light appeared on the young man's eyebrows - the doctor suddenly changed his face: "You kid... It's not simple!" So, who is pretending to have this disease?