I Rely on the Erhu to Kill Demons

Li Changan never thought that he came to this world because he was struck by lightning on the way back to his dormitory. As soon as he opened his eyes, he was faced with a painted ghost with a cracked neck and changing skin. There is no cultivation, no skills, only the cold system prompt in my mind: [If a demon is detected, please kill it immediately. Reward: Earthly Demonic Power - Sword Skill]. In order to survive, he had to pick up the sword and became an "amateur" demon slayer.