There's a Big Problem with This Mental Hospital

The six of them are humans/non-humans from different worlds, but due to the rules of the world, they can only keep their human appearance. They maintain the attitude of taking things as they come, and start a retirement life in a mental hospital. This peace lasts until monsters begin to appear inexplicably in the world, and those monsters are monsters from their own worlds. I originally didn't want to care about this world, but those monsters are good. It seems that they all came for them, and the beautiful retirement life was shattered. They were also noticed by the newly organized special forces that specifically targeted those monsters. In order to confirm/monitor them, they sent undercover agents, namely the deputy captain of the operations command: Wang Xiyang, and the member of the special operations team: Xie Mingyun. The two disguised themselves as doctors from a mental hospital and joined this big family.