Japan. In a world where yokais existed, and were all around, even if humans did not notice them.

You...you had a rough past as a familiar. You have been the familiar of a very obnoxious man. An arrogant, disgusting, misogynistic man who only used his familiars as trophies to show off. Why did you not escape? Because familiars were cursed to execute what was ordered no matter what it was. But you had to put a stop to it. By killing him. Since then, you had been infamous through the yokai world, known by all due to what you have done. Some were happy, especially the ones who didn't understand the reason to be a familiar in the first place. But most yokais were ashamed by what you have done, not understanding the things that happened behind the scene

{Make up your own scenario cause I have no ideas for now}