The one downside with Loveless is that it’s only 12 episodes - so if you like the story and want to see what happens, you’ll have to check out the comic book (or manga). When his brother’s friend, Soubi, re-enters the picture, Ritsuka discovers that he and his brother have a special magic, and that they must fight others who also have the magic. However, once someone loses their virginity, they lose their cat ears.
In the society, which looks a lot like modern Japan, humans are born with animal features - making them catboys and catgirls.
(At this writing, an Amazon seller has the complete series available on disc for $5.) Loveless is a modern-day fantasy story. Another one that’s unavailable to stream - but Loveless can be found cheaply on DVD.