Black cats get a rap for bringing bad luck. We’re pretty sure that it’s a stereotype perpetrated by people whose lives had already been shit looking for a scape-cat.
These inky guardians of the underworld instead prevent the monsters and goblins from escaping into our world, at least according to the beliefs of at least one ancient culture.
The black voids of Mandarin’s Retreat do a lot of guarding too, though primarily of the treat and catnip cupboard. Every household should have at least one house panther keeping watch.