Demon Slayer: Run! Both He and the System Are Mentally Ill.

[Monster killing + funny + invincible + mental illness + cool article] Chen Ye is a mental patient. He has been an alien, a killer, and a doctor... But now he thinks he is in a game world because of his cognitive impairment! The police officers and monster slayers who fight monsters are all players like him! Those ordinary people are NPCs in the game world who can issue tasks! So with the help of the same abnormal system, he decided to become an expert in the game! Become a game king! So the world has an extra demon-slayer suffering from mental illness - codename: Dongdongguai!