From the comic strips drawn by Virgo, it appeared that the cat people lived in the swamps. Food wasn't a problem for them, but for the cleanliness-loving feline race, the swamp environment was indeed a source of suffering.
Then there was the issue of their nocturnal nature. The cat people had considered relocating to Dark City before, but unfortunately, they were rejected by the Dark Elves. The reason was that many, including Dark Queen Fred, were allergic to cats...
But now, with the advent of the City of Eternal Night, it presented a better alternative for the cat people than Dark City: the City of Eternal Night, floating in the sky, maintained the characteristic of eternal night, and yet there was no need to stay underground in a confined, dark place all the time. If they wished to bask in the sunlight, they could simply leave the city at any time, making it an ideal gathering place for the cat people!