Ravens Castle located in the Kingdom of Blackmoon was an enormous military fortress. The population used to be scarce, but recently, Ravens Castle was visited by many people.
These were the people who escaped from the Kingdom of Light. Some were refugees, some were businessmen, some were small aristocrats; all of them wanted to make their way into Ravens Castle.
That was because Ravens Castle was the only entrance leading to the Kingdom of Blackmoon. Otherwise, they would have to go through thousands of miles of deserted mountains.
The deserted mountains contained with them all sorts of dangers. Almost no one had crossed the barren mountains to get into the Kingdom of Blackmoon. Therefore, the deserted mountains became a natural barrier between the Kingdom of Blackmoon and the Kingdom of Light.