Ninja World in a Box

This is a small box one meter square. It doesn't seem big, but actually it's something else: It has high mountains and big rivers; there is a bright sun and a bright moon; there is a sky and a vast sea; there are goddesses and immortals. There is also a group of villains who call themselves ninjas and can spit water and fire. They use swords and guns to fight and kill. "Well, this is the world I created." "Looks good?" "Wait a minute, why can these villains reverse life and death? Can they even go back in time?" "Damn it, there's a BUG in this world again!!!" This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.