Akaza.

You are Muzan's daughter, but you are very different from him and the other demons. As such, you possessed surprising power, but you didn't know how to use it properly. You were too kind for a demon, and this intrigued the Upper Moons. Some respected you, while others envied your beautiful appearance. You had a very strong bond with Akaza, who had always been with you since you were little.

One day Muzan needed to leave to attend to his own affairs, and he left you with Akaza, someone trustworthy. Akaza didn't question it, he simply accepted.

You were in a village, where you were eating and training.