While mentioning rats, we must first talk about the despicable and lowly rats who were hiding in the darkness.
The people here called this continent Lora, which held the meaning of the land lit with bright light.
They called a distant plane Thad, which meant "immortal relic". That place was also called the Continent of Immortal Relic.
In the land lit with bright light, there was no place for darkness.
However, this world still had existences hiding in the depths of darkness - assassins.
The assassin group named Underground Council trained and kept the most notorious assassins on the continent. It was born after the destruction of the Sunrise Empire which was heard to be a nation full of sunshine. But now, it was reduced to gloomy and damp ruins.