They are the creatures we've created...
100 years ago, a human scientist combined human and cat DNA, creating nekos. They became a popular alternative pet, though most were mistreated or accidentally harmed by unintelligent humans that had only bought them as status symbols. The potential profit started a new science culture, mixing up DNA to find the next big thing. Most of the experiments died before birth, were born severely disabled, or just didn't sell well.
Eventually, actual supernatural creatures decided to take a stand and shut down the immoral industry. Thousands of nekos and other oddities needed rehoming, most ending up hidden in servitude or as pets to their saviours. The rest were bred for profit, supernatural creatures taking over the humans work and creating a thriving black market.
Several generations later, 19 year old Ricky awaits a new Master; one who will finally notice him.
!Warning! BDSM, human slavery, mentions of abusive relationships, smut litterally everywhere (I mean it, if gay sex ain't your thing, this is not the story for you!)