Is it just a Rumor or what? Continuation to this.
>A long time ago, it is said that a large meteor came from the sky containing a terrifying monster. It was said that at night the monster would appear in the town along with the cold winds and take away humans and Pokémon to eat them. Eventually, the residents of the town surrounded Lacunosa Town in a wall to keep the monster out and rule was then set on the town that forbade anyone from leaving at night and encouraged people to stay in their homes. Even though Lacunosa residents claim to no longer believe this old story, they still stay inside of their houses at night and the walls remain standing to this day.
Its just supposedly how Kyurem came to be where it is. Nothing Special.